Question

if cos x=cos 40.sin 50.sin40.cos 59.then find value of x

Answer 1

the value of x is =  1

Answer 2

Answer

cos x = cos 40 sin 50 + sin 40 cos 50

cos x = sin^2 50 + cos^2 50 [sin Ø = cos (90 - Ø), and vice versa]

cos x = 1 [sin^2 Ø + cos^2 Ø = 1]

cos x = 0, when x = 0°

.°. x = 0