Question

Bentuk sederhana dari 4 sin(1/4 ∏ + x) cos(1/4 ∏ - x) adalah

Answer 1

Verified answer

Jawab

2 sin a cos b  = sin a + sin b

4 sin (1/4π + x)  cos (1/4π - x) =
= 2 { 2 sin (1/4 π + x) cos (1/4 π -x)}
= 2 { sin (1/4 π+x + 1/4  π - x) cos (1/4 π + x - 1/4 π + x)}
= 2 (sin π/2  cos 2x)
= 2 (1)(cos 2x)
= 2 cos 2x