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.