Answer and explanation

Correct answer: C. ln|sec x| + C

  1. Step 1: Rewrite tan x = sin x / cos x. Let u = cos x, du = -sin x dx. Step 2. Integral is -ln|cos x| + C = ln|1/cos x| + C = ln|sec x| + C. Answer: ln|sec x| + C. Why not the others: sec^2 x is the derivative of tan x; ln|cos x| misses the required minus sign; -ln|sec x| flips the sign.

Practise more Calculus - Limits, Differential and Integral Calculus.

Free questions with an explanation for every one, and full timed Higher Secondary Certificate Examination (Bangladesh) mock tests.