Question

prove (sinx + cosx)^2 = 1 + sin 2x

Answer 1

So just square it and look at the pythagorean identity. Then you'll see that there should be just one other identity, and you're looking straight at it.

Answer 2

1) factor out the left side
2) subtract from both sides whatever you can

do you get a trigonometric identity?

Answer 3

i mean foil the left side.... whatever, you know what i mean.

Answer 4

Expand the LHS, and use the double-angle formula and the Pythagorean Identity