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NCERT Class XII Mathematics Chapter - - Solutions

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Exercise - 7.6
Integrate the functions in Exercises 134 to 155.
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Question : 152 of 271
Marks: +1, -0
ex(1x−1x2)e^x\left(\frac{1}{x}-\frac{1}{x^2}\right)
Solution:  
Let I=∫ex(1x−1x2)dxI=\int e^x\left(\frac{1}{x}-\frac{1}{x^2}\right)dx
=∫ex(1x+ddx(1x))dx=\int e^x\left(\frac{1}{x}+\frac{d}{dx}\left(\frac{1}{x}\right)\right)dx
=ex×1x+C=e^x\times\frac{1}{x}+C
=exx+C=\frac{e^x}{x}+C [∵∫ex(f(x)+f′(x))dx=exf(x)+C]\left[\because \int e^x\left(f(x)+f'(x)\right)dx = e^x f(x)+C\right]
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