If $C(16,r) = C(16,r+2)$, then find $r$. Explain how you know.











up vote
2
down vote

favorite
1













If $C(16,r) = C(16,r+2)$, then find $r$. Explain how you know.




Just started dealing with combinations and permutations rights now and came across this study problem. I've converted each side into their combination formula forms, but I'm not sure where to go from there(or even if that's what I should be doing). Any help with this or at least where I should start?










share|cite|improve this question




























    up vote
    2
    down vote

    favorite
    1













    If $C(16,r) = C(16,r+2)$, then find $r$. Explain how you know.




    Just started dealing with combinations and permutations rights now and came across this study problem. I've converted each side into their combination formula forms, but I'm not sure where to go from there(or even if that's what I should be doing). Any help with this or at least where I should start?










    share|cite|improve this question


























      up vote
      2
      down vote

      favorite
      1









      up vote
      2
      down vote

      favorite
      1






      1






      If $C(16,r) = C(16,r+2)$, then find $r$. Explain how you know.




      Just started dealing with combinations and permutations rights now and came across this study problem. I've converted each side into their combination formula forms, but I'm not sure where to go from there(or even if that's what I should be doing). Any help with this or at least where I should start?










      share|cite|improve this question
















      If $C(16,r) = C(16,r+2)$, then find $r$. Explain how you know.




      Just started dealing with combinations and permutations rights now and came across this study problem. I've converted each side into their combination formula forms, but I'm not sure where to go from there(or even if that's what I should be doing). Any help with this or at least where I should start?







      combinations






      share|cite|improve this question















      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Dec 3 at 9:23









      Tianlalu

      3,0001937




      3,0001937










      asked Dec 3 at 4:23









      Gold Pony Boy

      152




      152






















          3 Answers
          3






          active

          oldest

          votes

















          up vote
          3
          down vote



          accepted










          Note that $binom{n}{k} = binom{n}{n-k}.$



          What equation does this give for $r$ in your scenario? What is the solution to that equation?



          Note that $binom{n}{a+1} > binom{n}{a}$ when $a < lfloor n/2 rfloor,$ hence an integer can be taken on at most twice as you range among $binom{n}{0}, dots, binom{n}{n}.$ Since $r ne r+2,$ the value of $r$ that you find is unique.






          share|cite|improve this answer























          • Your equation does not imply $$binom na=binom nbimplies a=n-b$$
            – Kemono Chen
            Dec 3 at 4:52












          • @KemonoChen Note that $binom{n}{a+1} > binom{n}{a}$ when $a < lfloor n/2 rfloor,$ hence an integer can be taken on at most twice as you range among $binom{n}{0}, dots, binom{n}{n}.$
            – Display name
            Dec 3 at 5:00












          • Exactly. I think it would be better to put this into your answer to clarify. :P The original answer is logically incorrect.
            – Kemono Chen
            Dec 3 at 5:01


















          up vote
          4
          down vote













          Hint: Think about row $16$ of Pascal's triangle. When does it increase (going to the right) and when does it decrease? What values are duplicated and where?






          share|cite|improve this answer





















          • Okay, I see the connection now, so r must be 7...?
            – Gold Pony Boy
            Dec 3 at 4:45










          • @GoldPonyBoy Yes.
            – Carl Schildkraut
            Dec 3 at 6:06


















          up vote
          2
          down vote













          $C_r^{16}=C_{r+2}^{16}$
          Then using the definition of combination you'll get



          $$frac{16!}{r!(16-r)!}=frac{16!}{(r+2)!(16-r-2)!}$$
          $$implies frac{1}{r!(16-r)(15-r).(14-r)!}=frac{1}{(r+2)(r+1).r!.(14-r)!}$$
          $$implies (16-r)(15-r)=(r+2)(r+1)$$
          $$implies 240-31r+r^2=r^2+3r+2$$
          $$implies 34r=238$$
          $$implies r=7$$






          share|cite|improve this answer























          • Sorry, I must be stupid or something and my algebra is off, but i can't get from the last line to r = 7
            – Gold Pony Boy
            Dec 3 at 5:06






          • 2




            @GoldPonyBoy Just expand both sides, move everything to one side, and solve the quadratic equation.
            – mathematics2x2life
            Dec 3 at 5:07










          • @mathematics2x2life Oh I AM just dumb, I wrote -r*-r = -r^2. This is what I started to do originally, but couldn't follow the logic at first. Thanks for the help, I really appreciate it.
            – Gold Pony Boy
            Dec 3 at 5:12








          • 1




            @Gold Pony Boy we have that $(r+2)!=(r+2)(r+1).r!$ So you remove $r!$ both sides and you are left with $(r+1)(r+2)$ on the right side
            – Fareed AF
            Dec 3 at 5:30






          • 1




            This approach is true but massive overkill. Better to note that the denominator $D(r) = r!(16−r)!$ is monotonic increasing for r < floor(n/2), achieves a maximum at n/2 = 8, and is symmetric about floor(n/2). From that we can directly conclude that if D(x) = D(y), then we must have y = n-x
            – smci
            Dec 3 at 17:46













          Your Answer





          StackExchange.ifUsing("editor", function () {
          return StackExchange.using("mathjaxEditing", function () {
          StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
          StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
          });
          });
          }, "mathjax-editing");

          StackExchange.ready(function() {
          var channelOptions = {
          tags: "".split(" "),
          id: "69"
          };
          initTagRenderer("".split(" "), "".split(" "), channelOptions);

          StackExchange.using("externalEditor", function() {
          // Have to fire editor after snippets, if snippets enabled
          if (StackExchange.settings.snippets.snippetsEnabled) {
          StackExchange.using("snippets", function() {
          createEditor();
          });
          }
          else {
          createEditor();
          }
          });

          function createEditor() {
          StackExchange.prepareEditor({
          heartbeatType: 'answer',
          convertImagesToLinks: true,
          noModals: true,
          showLowRepImageUploadWarning: true,
          reputationToPostImages: 10,
          bindNavPrevention: true,
          postfix: "",
          imageUploader: {
          brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
          contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
          allowUrls: true
          },
          noCode: true, onDemand: true,
          discardSelector: ".discard-answer"
          ,immediatelyShowMarkdownHelp:true
          });


          }
          });














          draft saved

          draft discarded


















          StackExchange.ready(
          function () {
          StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3023625%2fif-c16-r-c16-r2-then-find-r-explain-how-you-know%23new-answer', 'question_page');
          }
          );

          Post as a guest















          Required, but never shown

























          3 Answers
          3






          active

          oldest

          votes








          3 Answers
          3






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes








          up vote
          3
          down vote



          accepted










          Note that $binom{n}{k} = binom{n}{n-k}.$



          What equation does this give for $r$ in your scenario? What is the solution to that equation?



          Note that $binom{n}{a+1} > binom{n}{a}$ when $a < lfloor n/2 rfloor,$ hence an integer can be taken on at most twice as you range among $binom{n}{0}, dots, binom{n}{n}.$ Since $r ne r+2,$ the value of $r$ that you find is unique.






          share|cite|improve this answer























          • Your equation does not imply $$binom na=binom nbimplies a=n-b$$
            – Kemono Chen
            Dec 3 at 4:52












          • @KemonoChen Note that $binom{n}{a+1} > binom{n}{a}$ when $a < lfloor n/2 rfloor,$ hence an integer can be taken on at most twice as you range among $binom{n}{0}, dots, binom{n}{n}.$
            – Display name
            Dec 3 at 5:00












          • Exactly. I think it would be better to put this into your answer to clarify. :P The original answer is logically incorrect.
            – Kemono Chen
            Dec 3 at 5:01















          up vote
          3
          down vote



          accepted










          Note that $binom{n}{k} = binom{n}{n-k}.$



          What equation does this give for $r$ in your scenario? What is the solution to that equation?



          Note that $binom{n}{a+1} > binom{n}{a}$ when $a < lfloor n/2 rfloor,$ hence an integer can be taken on at most twice as you range among $binom{n}{0}, dots, binom{n}{n}.$ Since $r ne r+2,$ the value of $r$ that you find is unique.






          share|cite|improve this answer























          • Your equation does not imply $$binom na=binom nbimplies a=n-b$$
            – Kemono Chen
            Dec 3 at 4:52












          • @KemonoChen Note that $binom{n}{a+1} > binom{n}{a}$ when $a < lfloor n/2 rfloor,$ hence an integer can be taken on at most twice as you range among $binom{n}{0}, dots, binom{n}{n}.$
            – Display name
            Dec 3 at 5:00












          • Exactly. I think it would be better to put this into your answer to clarify. :P The original answer is logically incorrect.
            – Kemono Chen
            Dec 3 at 5:01













          up vote
          3
          down vote



          accepted







          up vote
          3
          down vote



          accepted






          Note that $binom{n}{k} = binom{n}{n-k}.$



          What equation does this give for $r$ in your scenario? What is the solution to that equation?



          Note that $binom{n}{a+1} > binom{n}{a}$ when $a < lfloor n/2 rfloor,$ hence an integer can be taken on at most twice as you range among $binom{n}{0}, dots, binom{n}{n}.$ Since $r ne r+2,$ the value of $r$ that you find is unique.






          share|cite|improve this answer














          Note that $binom{n}{k} = binom{n}{n-k}.$



          What equation does this give for $r$ in your scenario? What is the solution to that equation?



          Note that $binom{n}{a+1} > binom{n}{a}$ when $a < lfloor n/2 rfloor,$ hence an integer can be taken on at most twice as you range among $binom{n}{0}, dots, binom{n}{n}.$ Since $r ne r+2,$ the value of $r$ that you find is unique.







          share|cite|improve this answer














          share|cite|improve this answer



          share|cite|improve this answer








          edited Dec 3 at 6:35

























          answered Dec 3 at 4:28









          Display name

          789313




          789313












          • Your equation does not imply $$binom na=binom nbimplies a=n-b$$
            – Kemono Chen
            Dec 3 at 4:52












          • @KemonoChen Note that $binom{n}{a+1} > binom{n}{a}$ when $a < lfloor n/2 rfloor,$ hence an integer can be taken on at most twice as you range among $binom{n}{0}, dots, binom{n}{n}.$
            – Display name
            Dec 3 at 5:00












          • Exactly. I think it would be better to put this into your answer to clarify. :P The original answer is logically incorrect.
            – Kemono Chen
            Dec 3 at 5:01


















          • Your equation does not imply $$binom na=binom nbimplies a=n-b$$
            – Kemono Chen
            Dec 3 at 4:52












          • @KemonoChen Note that $binom{n}{a+1} > binom{n}{a}$ when $a < lfloor n/2 rfloor,$ hence an integer can be taken on at most twice as you range among $binom{n}{0}, dots, binom{n}{n}.$
            – Display name
            Dec 3 at 5:00












          • Exactly. I think it would be better to put this into your answer to clarify. :P The original answer is logically incorrect.
            – Kemono Chen
            Dec 3 at 5:01
















          Your equation does not imply $$binom na=binom nbimplies a=n-b$$
          – Kemono Chen
          Dec 3 at 4:52






          Your equation does not imply $$binom na=binom nbimplies a=n-b$$
          – Kemono Chen
          Dec 3 at 4:52














          @KemonoChen Note that $binom{n}{a+1} > binom{n}{a}$ when $a < lfloor n/2 rfloor,$ hence an integer can be taken on at most twice as you range among $binom{n}{0}, dots, binom{n}{n}.$
          – Display name
          Dec 3 at 5:00






          @KemonoChen Note that $binom{n}{a+1} > binom{n}{a}$ when $a < lfloor n/2 rfloor,$ hence an integer can be taken on at most twice as you range among $binom{n}{0}, dots, binom{n}{n}.$
          – Display name
          Dec 3 at 5:00














          Exactly. I think it would be better to put this into your answer to clarify. :P The original answer is logically incorrect.
          – Kemono Chen
          Dec 3 at 5:01




          Exactly. I think it would be better to put this into your answer to clarify. :P The original answer is logically incorrect.
          – Kemono Chen
          Dec 3 at 5:01










          up vote
          4
          down vote













          Hint: Think about row $16$ of Pascal's triangle. When does it increase (going to the right) and when does it decrease? What values are duplicated and where?






          share|cite|improve this answer





















          • Okay, I see the connection now, so r must be 7...?
            – Gold Pony Boy
            Dec 3 at 4:45










          • @GoldPonyBoy Yes.
            – Carl Schildkraut
            Dec 3 at 6:06















          up vote
          4
          down vote













          Hint: Think about row $16$ of Pascal's triangle. When does it increase (going to the right) and when does it decrease? What values are duplicated and where?






          share|cite|improve this answer





















          • Okay, I see the connection now, so r must be 7...?
            – Gold Pony Boy
            Dec 3 at 4:45










          • @GoldPonyBoy Yes.
            – Carl Schildkraut
            Dec 3 at 6:06













          up vote
          4
          down vote










          up vote
          4
          down vote









          Hint: Think about row $16$ of Pascal's triangle. When does it increase (going to the right) and when does it decrease? What values are duplicated and where?






          share|cite|improve this answer












          Hint: Think about row $16$ of Pascal's triangle. When does it increase (going to the right) and when does it decrease? What values are duplicated and where?







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Dec 3 at 4:29









          Carl Schildkraut

          11k11439




          11k11439












          • Okay, I see the connection now, so r must be 7...?
            – Gold Pony Boy
            Dec 3 at 4:45










          • @GoldPonyBoy Yes.
            – Carl Schildkraut
            Dec 3 at 6:06


















          • Okay, I see the connection now, so r must be 7...?
            – Gold Pony Boy
            Dec 3 at 4:45










          • @GoldPonyBoy Yes.
            – Carl Schildkraut
            Dec 3 at 6:06
















          Okay, I see the connection now, so r must be 7...?
          – Gold Pony Boy
          Dec 3 at 4:45




          Okay, I see the connection now, so r must be 7...?
          – Gold Pony Boy
          Dec 3 at 4:45












          @GoldPonyBoy Yes.
          – Carl Schildkraut
          Dec 3 at 6:06




          @GoldPonyBoy Yes.
          – Carl Schildkraut
          Dec 3 at 6:06










          up vote
          2
          down vote













          $C_r^{16}=C_{r+2}^{16}$
          Then using the definition of combination you'll get



          $$frac{16!}{r!(16-r)!}=frac{16!}{(r+2)!(16-r-2)!}$$
          $$implies frac{1}{r!(16-r)(15-r).(14-r)!}=frac{1}{(r+2)(r+1).r!.(14-r)!}$$
          $$implies (16-r)(15-r)=(r+2)(r+1)$$
          $$implies 240-31r+r^2=r^2+3r+2$$
          $$implies 34r=238$$
          $$implies r=7$$






          share|cite|improve this answer























          • Sorry, I must be stupid or something and my algebra is off, but i can't get from the last line to r = 7
            – Gold Pony Boy
            Dec 3 at 5:06






          • 2




            @GoldPonyBoy Just expand both sides, move everything to one side, and solve the quadratic equation.
            – mathematics2x2life
            Dec 3 at 5:07










          • @mathematics2x2life Oh I AM just dumb, I wrote -r*-r = -r^2. This is what I started to do originally, but couldn't follow the logic at first. Thanks for the help, I really appreciate it.
            – Gold Pony Boy
            Dec 3 at 5:12








          • 1




            @Gold Pony Boy we have that $(r+2)!=(r+2)(r+1).r!$ So you remove $r!$ both sides and you are left with $(r+1)(r+2)$ on the right side
            – Fareed AF
            Dec 3 at 5:30






          • 1




            This approach is true but massive overkill. Better to note that the denominator $D(r) = r!(16−r)!$ is monotonic increasing for r < floor(n/2), achieves a maximum at n/2 = 8, and is symmetric about floor(n/2). From that we can directly conclude that if D(x) = D(y), then we must have y = n-x
            – smci
            Dec 3 at 17:46

















          up vote
          2
          down vote













          $C_r^{16}=C_{r+2}^{16}$
          Then using the definition of combination you'll get



          $$frac{16!}{r!(16-r)!}=frac{16!}{(r+2)!(16-r-2)!}$$
          $$implies frac{1}{r!(16-r)(15-r).(14-r)!}=frac{1}{(r+2)(r+1).r!.(14-r)!}$$
          $$implies (16-r)(15-r)=(r+2)(r+1)$$
          $$implies 240-31r+r^2=r^2+3r+2$$
          $$implies 34r=238$$
          $$implies r=7$$






          share|cite|improve this answer























          • Sorry, I must be stupid or something and my algebra is off, but i can't get from the last line to r = 7
            – Gold Pony Boy
            Dec 3 at 5:06






          • 2




            @GoldPonyBoy Just expand both sides, move everything to one side, and solve the quadratic equation.
            – mathematics2x2life
            Dec 3 at 5:07










          • @mathematics2x2life Oh I AM just dumb, I wrote -r*-r = -r^2. This is what I started to do originally, but couldn't follow the logic at first. Thanks for the help, I really appreciate it.
            – Gold Pony Boy
            Dec 3 at 5:12








          • 1




            @Gold Pony Boy we have that $(r+2)!=(r+2)(r+1).r!$ So you remove $r!$ both sides and you are left with $(r+1)(r+2)$ on the right side
            – Fareed AF
            Dec 3 at 5:30






          • 1




            This approach is true but massive overkill. Better to note that the denominator $D(r) = r!(16−r)!$ is monotonic increasing for r < floor(n/2), achieves a maximum at n/2 = 8, and is symmetric about floor(n/2). From that we can directly conclude that if D(x) = D(y), then we must have y = n-x
            – smci
            Dec 3 at 17:46















          up vote
          2
          down vote










          up vote
          2
          down vote









          $C_r^{16}=C_{r+2}^{16}$
          Then using the definition of combination you'll get



          $$frac{16!}{r!(16-r)!}=frac{16!}{(r+2)!(16-r-2)!}$$
          $$implies frac{1}{r!(16-r)(15-r).(14-r)!}=frac{1}{(r+2)(r+1).r!.(14-r)!}$$
          $$implies (16-r)(15-r)=(r+2)(r+1)$$
          $$implies 240-31r+r^2=r^2+3r+2$$
          $$implies 34r=238$$
          $$implies r=7$$






          share|cite|improve this answer














          $C_r^{16}=C_{r+2}^{16}$
          Then using the definition of combination you'll get



          $$frac{16!}{r!(16-r)!}=frac{16!}{(r+2)!(16-r-2)!}$$
          $$implies frac{1}{r!(16-r)(15-r).(14-r)!}=frac{1}{(r+2)(r+1).r!.(14-r)!}$$
          $$implies (16-r)(15-r)=(r+2)(r+1)$$
          $$implies 240-31r+r^2=r^2+3r+2$$
          $$implies 34r=238$$
          $$implies r=7$$







          share|cite|improve this answer














          share|cite|improve this answer



          share|cite|improve this answer








          edited Dec 3 at 6:50

























          answered Dec 3 at 4:41









          Fareed AF

          41711




          41711












          • Sorry, I must be stupid or something and my algebra is off, but i can't get from the last line to r = 7
            – Gold Pony Boy
            Dec 3 at 5:06






          • 2




            @GoldPonyBoy Just expand both sides, move everything to one side, and solve the quadratic equation.
            – mathematics2x2life
            Dec 3 at 5:07










          • @mathematics2x2life Oh I AM just dumb, I wrote -r*-r = -r^2. This is what I started to do originally, but couldn't follow the logic at first. Thanks for the help, I really appreciate it.
            – Gold Pony Boy
            Dec 3 at 5:12








          • 1




            @Gold Pony Boy we have that $(r+2)!=(r+2)(r+1).r!$ So you remove $r!$ both sides and you are left with $(r+1)(r+2)$ on the right side
            – Fareed AF
            Dec 3 at 5:30






          • 1




            This approach is true but massive overkill. Better to note that the denominator $D(r) = r!(16−r)!$ is monotonic increasing for r < floor(n/2), achieves a maximum at n/2 = 8, and is symmetric about floor(n/2). From that we can directly conclude that if D(x) = D(y), then we must have y = n-x
            – smci
            Dec 3 at 17:46




















          • Sorry, I must be stupid or something and my algebra is off, but i can't get from the last line to r = 7
            – Gold Pony Boy
            Dec 3 at 5:06






          • 2




            @GoldPonyBoy Just expand both sides, move everything to one side, and solve the quadratic equation.
            – mathematics2x2life
            Dec 3 at 5:07










          • @mathematics2x2life Oh I AM just dumb, I wrote -r*-r = -r^2. This is what I started to do originally, but couldn't follow the logic at first. Thanks for the help, I really appreciate it.
            – Gold Pony Boy
            Dec 3 at 5:12








          • 1




            @Gold Pony Boy we have that $(r+2)!=(r+2)(r+1).r!$ So you remove $r!$ both sides and you are left with $(r+1)(r+2)$ on the right side
            – Fareed AF
            Dec 3 at 5:30






          • 1




            This approach is true but massive overkill. Better to note that the denominator $D(r) = r!(16−r)!$ is monotonic increasing for r < floor(n/2), achieves a maximum at n/2 = 8, and is symmetric about floor(n/2). From that we can directly conclude that if D(x) = D(y), then we must have y = n-x
            – smci
            Dec 3 at 17:46


















          Sorry, I must be stupid or something and my algebra is off, but i can't get from the last line to r = 7
          – Gold Pony Boy
          Dec 3 at 5:06




          Sorry, I must be stupid or something and my algebra is off, but i can't get from the last line to r = 7
          – Gold Pony Boy
          Dec 3 at 5:06




          2




          2




          @GoldPonyBoy Just expand both sides, move everything to one side, and solve the quadratic equation.
          – mathematics2x2life
          Dec 3 at 5:07




          @GoldPonyBoy Just expand both sides, move everything to one side, and solve the quadratic equation.
          – mathematics2x2life
          Dec 3 at 5:07












          @mathematics2x2life Oh I AM just dumb, I wrote -r*-r = -r^2. This is what I started to do originally, but couldn't follow the logic at first. Thanks for the help, I really appreciate it.
          – Gold Pony Boy
          Dec 3 at 5:12






          @mathematics2x2life Oh I AM just dumb, I wrote -r*-r = -r^2. This is what I started to do originally, but couldn't follow the logic at first. Thanks for the help, I really appreciate it.
          – Gold Pony Boy
          Dec 3 at 5:12






          1




          1




          @Gold Pony Boy we have that $(r+2)!=(r+2)(r+1).r!$ So you remove $r!$ both sides and you are left with $(r+1)(r+2)$ on the right side
          – Fareed AF
          Dec 3 at 5:30




          @Gold Pony Boy we have that $(r+2)!=(r+2)(r+1).r!$ So you remove $r!$ both sides and you are left with $(r+1)(r+2)$ on the right side
          – Fareed AF
          Dec 3 at 5:30




          1




          1




          This approach is true but massive overkill. Better to note that the denominator $D(r) = r!(16−r)!$ is monotonic increasing for r < floor(n/2), achieves a maximum at n/2 = 8, and is symmetric about floor(n/2). From that we can directly conclude that if D(x) = D(y), then we must have y = n-x
          – smci
          Dec 3 at 17:46






          This approach is true but massive overkill. Better to note that the denominator $D(r) = r!(16−r)!$ is monotonic increasing for r < floor(n/2), achieves a maximum at n/2 = 8, and is symmetric about floor(n/2). From that we can directly conclude that if D(x) = D(y), then we must have y = n-x
          – smci
          Dec 3 at 17:46




















          draft saved

          draft discarded




















































          Thanks for contributing an answer to Mathematics Stack Exchange!


          • Please be sure to answer the question. Provide details and share your research!

          But avoid



          • Asking for help, clarification, or responding to other answers.

          • Making statements based on opinion; back them up with references or personal experience.


          Use MathJax to format equations. MathJax reference.


          To learn more, see our tips on writing great answers.





          Some of your past answers have not been well-received, and you're in danger of being blocked from answering.


          Please pay close attention to the following guidance:


          • Please be sure to answer the question. Provide details and share your research!

          But avoid



          • Asking for help, clarification, or responding to other answers.

          • Making statements based on opinion; back them up with references or personal experience.


          To learn more, see our tips on writing great answers.




          draft saved


          draft discarded














          StackExchange.ready(
          function () {
          StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3023625%2fif-c16-r-c16-r2-then-find-r-explain-how-you-know%23new-answer', 'question_page');
          }
          );

          Post as a guest















          Required, but never shown





















































          Required, but never shown














          Required, but never shown












          Required, but never shown







          Required, but never shown

































          Required, but never shown














          Required, but never shown












          Required, but never shown







          Required, but never shown







          Popular posts from this blog

          flock() on closed filehandle LOCK_FILE at /usr/bin/apt-mirror

          Mangá

           ⁒  ․,‪⁊‑⁙ ⁖, ⁇‒※‌, †,⁖‗‌⁝    ‾‸⁘,‖⁔⁣,⁂‾
”‑,‥–,‬ ,⁀‹⁋‴⁑ ‒ ,‴⁋”‼ ⁨,‷⁔„ ‰′,‐‚ ‥‡‎“‷⁃⁨⁅⁣,⁔
⁇‘⁔⁡⁏⁌⁡‿‶‏⁨ ⁣⁕⁖⁨⁩⁥‽⁀  ‴‬⁜‟ ⁃‣‧⁕‮ …‍⁨‴ ⁩,⁚⁖‫ ,‵ ⁀,‮⁝‣‣ ⁑  ⁂– ․, ‾‽ ‏⁁“⁗‸ ‾… ‹‡⁌⁎‸‘ ‡⁏⁌‪ ‵⁛ ‎⁨ ―⁦⁤⁄⁕