Solving Trigonometric Equations

Question

Solve  on 

The solution(s) is/are 

Give your answers accurate to 3 decimal places

Answer 1

cosx = 0.54

The cosine function is positive in quadrants 1 and 4

So, x = Cos^-1(0.54) or 2π - Cos^-1(0.54) = 1.003592 or 5.282826

Answer 2

arccos 0.54 = 1.0003^r and 1.0003^r + π^r