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NCERT Class XII Mathematics Chapter - - Solutions

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Evaluate the definite integrals in Exercises 253 to 261.
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Question : 257 of 271
Marks: +1, -0
∫01dx1+x−x\int\limits_{0}^{1}\frac{dx}{\sqrt{1+x}-\sqrt{x}}
Solution:  
Let I=∫01dx1+x−xI=\int\limits_{0}^{1}\frac{dx}{\sqrt{1+x}-\sqrt{x}}
=∫011+x−x(1+x)−x dx=\int\limits_{0}^{1}\frac{\sqrt{1+x}-\sqrt{x}}{(1+x)-x}\,dx
=∫01[1+x−x] dx=\int\limits_{0}^{1}\left[\sqrt{1+x}-\sqrt{x}\right]\,dx
=[23(1+x)3/2]01+[23x3/2]01=\left[\frac{2}{3}(1+x)^{3/2}\right]_{0}^{1}+\left[\frac{2}{3}x^{3/2}\right]_{0}^{1}
=23(23/2−1)+23=\frac{2}{3}(2^{3/2}-1)+\frac{2}{3}
=23⋅23/2−23+23=\frac{2}{3}\cdot 2^{3/2}-\frac{2}{3}+\frac{2}{3}
=23⋅22=423=\frac{2}{3}\cdot 2\sqrt{2}=\frac{4\sqrt{2}}{3}
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