Question

can someone help me with six trig questions

Answer 1

@donbbb could you help me

Answer 2

use an angle sum identify to verify the identity

Answer 3

\[\cos 2\theta = 2 \cos^2 \theta - 1\]

Answer 4

@Jemurray3

Answer 5

@hawk36571

Answer 6

Try using
\[ \cos(x+y) = \cos(x) \cos(y) - \sin(x) \sin(y) \]