How do I simplify these trig functions so that the right and left sides are the same?
you could note that both sides are , but that would be too easy.
instead, use the fact that . start with the left hand side of the equation and use the identity i typed abpve to replace either the sine or cosine to get the right hand side
for number 5, I get
cos^2x - sin^2x = sin^2x + cos^2x - 2sin^2x
no.
start with the left hand side only. forget about the right. then use the identity i showed you to transform it into the right hand side (or vice versa, start with the right side and simplify to get the left)