Integral Calculus Question 445

Question: $ \int_{{}}^{{}}{\frac{t}{{e^{3t^{2}}}}\ dt=} $

[MP PET 1997]

Options:

A) $ \frac{1}{6}{e^{3t^{2}}}+c $

B) $ -\frac{1}{6}{e^{3t^{2}}}+c $

C) $ \frac{1}{6}{e^{-3t^{2}}}+c $

D) $ -\frac{1}{6}{e^{-3t^{2}}}+c $

Show Answer

Answer:

Correct Answer: D

Solution:

$ I=\int_{{}}^{{}}{t,.,{e^{-3t^{2}}}dt} $ Put $ -3t^{2}=z\Rightarrow -6t,dt=dz\Rightarrow t,dt=\frac{-1}{6},dz $
$ \therefore ,I=-\frac{1}{6}\int_{{}}^{{}}{e^{z}dt}=\frac{-e^{z}}{6}+c=-\frac{{e^{-3t^{2}}}}{6}+c. $