Question

Find values of x for sinx.sin3x=1/2

Answer 1

SinxSin3x = 1/2

2Sinxsin3x = 1

Cos(2x) - cos4x = 1

cos2x - ( cos^2( 2x) - sin^2(2x ) = 1

cos2x - 2cos^2(2x) + 1 = 1

cos2x = 2cos^2(2x)

cos2x = 1/2

2x = π/3

x = π/6