Hello!  This website will teach you how to verify trig identities.  Here are some trig identities that you will need to know:

Reciprocal Identities:

sin θ = 1/csc θ        cos θ = 1/sec θ        tan θ= 1/cot θ
csc θ = 1/sin θ        sec θ = 1/cos θ        cot θ= 1/tan θ

Quotient Identities:

tan θ = sin θ/cos θ        cot θ = cos θ/sin θ

Pythagorean Identities:

sin² θ + cos² = 1            1 + tan² θ = sec² θ           1 + cot² θ = csc² θ

Cofunction Identities:

sin(π/2 - θ) = cos θ        csc(π/2 - θ) = sec θ
cos(π/2 - θ) = sin θ        sec(π/2 - θ) = csc θ
tan(π/2 - θ) = cot θ         cot(π/2 - θ) = tan θ

Even/Odd Identities:

sin(-θ) = -sin θ       csc(-θ) = -csc θ
cos(-θ) = cos θ      sec(-θ) = sec θ
tan(-θ) = -tan θ       cot(-θ) = -cot θ