I am having trouble with simplifying Basic Trigonometric Identities. I have a homework with 15 problems which I don't understand anything about it. I have the three basic trig identities (reciprocal, quotient, and pythagorean) Can someone help me on my homework? I'll post a picture of one problem! Please! :(

Question

anonymous · Answer

Please help!

raden · Answer

just change tan into sin/cos, then simplify

cosx + sinxtanx
= cosx + sinx * sinx/cosx
= cos^2x/cosx + sin^2 x/cosx
= (cos^2 x + sin^2 x)/cosx
= 1/cosx
= sec(x)

anonymous · Answer

How would I know how to change them? :/