How to calculate the indefinite integral of $(x-1)^{frac 12}-(x-3)$?












4












$begingroup$


Why is the following integral wrong?



$$ int[(x-1)^{frac 12}-(x-3)]dx=frac 23 (x-1)^{frac32}-frac12(x-3)^2+c $$



The answer given by my textbook is:
$$ int[(x-1)^{frac 12}-(x-3)]dx=frac 23 (x-1)^{frac32}-frac12x^2+3x+c $$



I understand why the textbook's answer is right. But I don't understand what I did wrong in mine.










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    4












    $begingroup$


    Why is the following integral wrong?



    $$ int[(x-1)^{frac 12}-(x-3)]dx=frac 23 (x-1)^{frac32}-frac12(x-3)^2+c $$



    The answer given by my textbook is:
    $$ int[(x-1)^{frac 12}-(x-3)]dx=frac 23 (x-1)^{frac32}-frac12x^2+3x+c $$



    I understand why the textbook's answer is right. But I don't understand what I did wrong in mine.










    share|cite|improve this question











    $endgroup$















      4












      4








      4





      $begingroup$


      Why is the following integral wrong?



      $$ int[(x-1)^{frac 12}-(x-3)]dx=frac 23 (x-1)^{frac32}-frac12(x-3)^2+c $$



      The answer given by my textbook is:
      $$ int[(x-1)^{frac 12}-(x-3)]dx=frac 23 (x-1)^{frac32}-frac12x^2+3x+c $$



      I understand why the textbook's answer is right. But I don't understand what I did wrong in mine.










      share|cite|improve this question











      $endgroup$




      Why is the following integral wrong?



      $$ int[(x-1)^{frac 12}-(x-3)]dx=frac 23 (x-1)^{frac32}-frac12(x-3)^2+c $$



      The answer given by my textbook is:
      $$ int[(x-1)^{frac 12}-(x-3)]dx=frac 23 (x-1)^{frac32}-frac12x^2+3x+c $$



      I understand why the textbook's answer is right. But I don't understand what I did wrong in mine.







      calculus integration indefinite-integrals






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      share|cite|improve this question













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      edited Dec 9 '18 at 1:53









      AccidentalFourierTransform

      1,442827




      1,442827










      asked Dec 8 '18 at 21:46









      John ArgJohn Arg

      316




      316






















          1 Answer
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          7












          $begingroup$

          Note that
          begin{align}
          frac{2}{3}(x-1)^{3/2}-frac{1}{2}(x-3)^2+c &= frac{2}{3}(x-1)^{3/2}-frac{1}{2}(x^2-6x+9)+c\ &= frac{2}{3}(x-1)^{3/2}-frac{1}{2}x^2+3xunderbrace{-frac{9}{2}+c}_{text{constant}},
          end{align}

          so both answers are valid.






          share|cite|improve this answer











          $endgroup$













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            1 Answer
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            active

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            1 Answer
            1






            active

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            active

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            active

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            7












            $begingroup$

            Note that
            begin{align}
            frac{2}{3}(x-1)^{3/2}-frac{1}{2}(x-3)^2+c &= frac{2}{3}(x-1)^{3/2}-frac{1}{2}(x^2-6x+9)+c\ &= frac{2}{3}(x-1)^{3/2}-frac{1}{2}x^2+3xunderbrace{-frac{9}{2}+c}_{text{constant}},
            end{align}

            so both answers are valid.






            share|cite|improve this answer











            $endgroup$


















              7












              $begingroup$

              Note that
              begin{align}
              frac{2}{3}(x-1)^{3/2}-frac{1}{2}(x-3)^2+c &= frac{2}{3}(x-1)^{3/2}-frac{1}{2}(x^2-6x+9)+c\ &= frac{2}{3}(x-1)^{3/2}-frac{1}{2}x^2+3xunderbrace{-frac{9}{2}+c}_{text{constant}},
              end{align}

              so both answers are valid.






              share|cite|improve this answer











              $endgroup$
















                7












                7








                7





                $begingroup$

                Note that
                begin{align}
                frac{2}{3}(x-1)^{3/2}-frac{1}{2}(x-3)^2+c &= frac{2}{3}(x-1)^{3/2}-frac{1}{2}(x^2-6x+9)+c\ &= frac{2}{3}(x-1)^{3/2}-frac{1}{2}x^2+3xunderbrace{-frac{9}{2}+c}_{text{constant}},
                end{align}

                so both answers are valid.






                share|cite|improve this answer











                $endgroup$



                Note that
                begin{align}
                frac{2}{3}(x-1)^{3/2}-frac{1}{2}(x-3)^2+c &= frac{2}{3}(x-1)^{3/2}-frac{1}{2}(x^2-6x+9)+c\ &= frac{2}{3}(x-1)^{3/2}-frac{1}{2}x^2+3xunderbrace{-frac{9}{2}+c}_{text{constant}},
                end{align}

                so both answers are valid.







                share|cite|improve this answer














                share|cite|improve this answer



                share|cite|improve this answer








                edited Dec 8 '18 at 21:54

























                answered Dec 8 '18 at 21:48









                MisterRiemannMisterRiemann

                5,8571624




                5,8571624






























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