integration

∫dx/(1+√x)^2010= 2[1/alpha(1+√x)^alpha - 1/beta(1+√x)^beta] +c

where alpha, beta >0

A)|alpha-beta|=1
B)(beta+2)(alpha+1)=20102
C) beta and alpha are in A.P.
D)alpha+1=beta+2=2010

5 Answers

1708
man111 singh ·

\hspace{-16}$ Given $\int\frac{1}{(1+\sqrt{x})^{2010}}dx=2.\left\{\frac{1}{\alpha.(1+\ \sqrt{x})^{\alpha}}-\frac{1}{\beta.(1+\sqrt{x})^{\beta}}\right\}+C$\\\\\\ Now Calculating Value of $\int\frac{1}{(1+\sqrt{x})^{2010}}dx$\\\\\\ Put $(1+\sqrt{x})=t\Leftrightarrow \frac{1}{2.\sqrt{x}}dx=dt\Leftrightarrow dx=2\sqrt{x}dt=2.(t-1)dt$\\\\\\ $=\int\frac{2.(t-1)}{t^{2010}}dt=2.\left\{\int\frac{1}{t^{2009}}dt-\int\frac{1}{t^{2010}}dt\right\}$\\\\\\ $=2.\left\{-\frac{1}{2008}.\frac{1}{t^{2008}}+\frac{1}{2009}.\frac{1}{t^{2009}}\right\}+C$\\\\\\ $=2.\left\{-\frac{1}{2008}.\frac{1}{(1+\sqrt{x})^{2008}}+\frac{1}{2009}.\frac{1}{(1+\sqrt{x})^{2009}}\right\}+C$\\\\\\ So Here We get\\\\\\ $\int\frac{1}{(1+\sqrt{x})^{2010}}dx=2.\left\{\frac{1}{2009}.\frac{1}{(1+\sqrt{x})^{2009}}-\frac{1}{2008}.\frac{1}{(1+\sqrt{x})^{2008}}\right\}+C$\\\\\\ So From Here We Get $\boxed{\boxed{\mathbf{\alpha =2009}}}$ and $\boxed{\boxed{\mathbf{\beta =2008}}}$

21
Shubhodip ·

I got that without solving it :)

1708
man111 singh ·

How????

plz write here Shubhodip.

Thanks

21
Shubhodip ·

any of option C and D implies the rest..

and you r going to get a q where all options are correct :D

actually its easy..but i got scared in the exam

edit: LOL at the reply below....

1708
man111 singh ·

Yes You are saying Right Shubhodip.

again Thanks. for nice explanation.

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