ashokkumar
Mr
find the integral of x^3/sqrt(x^2+1)
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integration by sub. (1 Viewer)
- Thread starter ashokkumar
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I think answer is: 1/3 (1+x^2)^(3/2) - sqrt(1+x^2) + C
thongetsu
Where aren't I?
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thats what i had xD
ashokkumar
Mr
yup i got that too. the question is an example from Cambridge 4unit. However cambridge's answer was different.^{\frac{1}{2}}\ \ -\ x(1+x^{2})^{-\frac{1}{2}}\ dx\\ \\ =\ \ \frac{1}{2}\int (1+x^{2})^{\frac{1}{2}}\ -\ (1+x^{2})^{-\frac{1}{2}}\ d(1+x^{2})\\ \\ =\ \ \frac{1}{3}(1+x^{2})^{\frac{3}{2}}\ -\ \sqrt{1+x^{2}}\ +\ C)
hahaha