Trigonometric Functions:
If u is a function x, where u' dx = du, then
ò sin u du = -cos u + C
ò cos u du = sin u + C
ò sec2 u du = tan u + C
ò csc2 u du = -cot u + C
ò sec u tan u du = sec u + C
ò csc u cot u du = -csc u + C
Trigonometric identities can be used if possible to change the form of the integrand.