Question

How do you express `sin(pi/ 6 ) * cos( ( 5 pi) / 8 )` without using products of trigonometric functions?

Answer 1

`P = -(1/2)sin (pi/8)`

Explanation:

`P = sin (pi)/6.cos ((5pi)/8)`
Trig table --> sin (pi/6) = 1/2
Trig unit circle -->
`cos((5pi)/8) = cos (pi/8 + (4pi)/8) = cos (pi/8) + pi/2) = - sin (pi/8)`
(Complementary arcs)
#P = - (1/2)sin (pi/8)