Find all solutions if 0 x Solutiona cos 2x 12 2x cos112 2x

Solution

a) cos 2x = 1/2

2x = cos^-1(1/2)

2x = /4, 7/4

x = /8 , 7/8.

b) we have

sinA.cosB + cosA.sinB = sin(A+B)

considering A=2x & B = x , the given equation becomes

sin(2x+x) = 1/2

sin3x = 1/2

3x = sin^-1(1/2)

3x = /6 , 5/6

x = /18 , 5/18.