Question bank/JEE Main/Mathematics

JEE MainMathematicsModerateIndefinite integration

If C is arbitrary constant
then 
∫ax1−a2xdx=\int\frac{a^{x}}{\sqrt{1 - a^{2x}}}dx =

Show answer and solution
Let 
I=∫ax1−a2xdx.I = \int\frac{a^{x}}{\sqrt{1 - a^{2x}}}dx. Put ax=ta^{x} = t
 So that
axlog⁡eadx=dta^{x}\log_{e}adx = dt or dx=dt/(axlog⁡ea)dx = dt/(a^{x}\log_{e}a)
∴ \therefore\
I=1log⁡ea∫dt12−t2I = \frac{1}{\log_{e}a}\int\frac{dt}{\sqrt{1^{2} - t^{2}}}
=1log⁡ea⋅sin⁡−1(t)+C=1log⁡easin⁡−1(ax)+C= \frac{1}{\log_{e}a} \cdot \sin^{- 1}(t) + C = \frac{1}{\log_{e}a}\sin^{- 1}\left( a^{x} \right) + C

Source: Grass-G / M-12 Mathematics Paper 2 Nov.docx

Need a video for this idea?

Scan any doubt from your notes and get a whiteboard explanation.