Derivatives and integrals of trig functions are easier to remeber when they are remembered in pairs that correspond to each other. Check this out:
1. Derivative of sin x is cos x; the integral of cos x therefore equals sin x +c;
2. Derivative of cos x is -sin x, so the integral of sin x is -cos x +c;
3. Derivative of tan x is sec2x, therefore the integral of sec2x is tan x + c;
4. Derivative of cot x is -csc2x, therefore the integral of csc2x is -cot x +c;
5. Derivative of sec x is sec x * tan x, so we figure out the integral of sec x * tan x would be sec x + c;
6. Derivative of csc x is -csc x * cot x, and so we figure out the integral of csc x * cot x would be -csc x + c.