Answer
$$
\int \sec^2x\tan xdx
=\frac{1}{2}\tan^2x +c
$$
Work Step by Step
Since $ u=\tan x $, then $ du=\sec^2x dx $ and hence, $$
\int \sec^2x\tan xdx =\int u d u= \frac{1}{2}u^2 +c\\
=\frac{1}{2}\tan^2x +c
$$
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.