Practicing Success
$I=\int \frac{1}{\sqrt{1-e^{2 x}}} d x$ is equal to |
$\ln \left|\frac{\sin ^{-1} e^x}{2}\right|+c$ $\tan \ln \left|\frac{\sin ^{-1} e^x}{2}\right|+c$ $\ln \left|\tan \left(\frac{\sin ^{-1} e^x}{2}\right)\right|+c$ none of these |
$\ln \left|\tan \left(\frac{\sin ^{-1} e^x}{2}\right)\right|+c$ |
$e^{x}=t$ $e^{x} dx=dt$ $\int \frac{d t}{t \sqrt{1-t^2}}$, put $\sin ^{-1} t=z$ $\frac{1}{\sqrt{1-t^2}} d t=d z=\int \frac{d z}{\sin z}=\int ~cosec~z d z=\ln \left|\tan \frac{z}{2}\right|+k$ $=\ln \left|\tan \left(\frac{\sin ^{-1} e^x}{2}\right)\right|+k$ Hence (3) is the correct answer. |