Question

if sin (20+theta) = cos30° , then find theta

Answer 1

sin (20+theta) = cos30
sin (20+theta) = sin(90-30)
20 + theta = 60
theta = 60-20
theta = 40

Answer 2

sin(20+theta)=sin(90-30)
sin(20+theta)=sin(60)

20+theta = n(180) + ((-1)^n)60
theta = n(180) + ((-1)^n)60 - 20