Question

1) nilai x dari sin(2x-30)=cos 20
2) NIlai x dari cos 2x =sinx

Answer 1

Mungkin seperti ini... :)
sin(2x - 30) = cos 20
sin(2x - 30) = sin(90 - 20)
2x - 30 = 90 - 20 + k.360
2x - 10 = 90 + k.360
2x = 100 + k.360
x = 50 + k.180
k = 0 ===> x = 50