Question

how do i prove this using trig identity: (2sinx+3cosx)^2+(3sinx-2cosx)^2=13

Answer 1

i did this on my calculator type it in your calulator just as your type on here tell me what you get

Answer 2

i have to prove it using trigonometric identity without a calculator

Answer 3

First, use foil to expand them. Then use the following identity
\[
\sin^2(\theta)+\cos^2(\theta)=1
\]

Answer 4

what do i do with the leading coefficients?

Answer 5

Factor them out.

Answer 6

What did you get?