Solve the multiple angle expression. cos(3x/6)=√2/2

Question

Solve the multiple angle expression. cos(3x/6)=√2/2

Answer 1

Notice that 3x/6 = x/2

Also, observe your unit circle to find that cos(θ) = √2/2 when θ = pi/4 and when θ = 7pi/4

Therefore, we just need to solve for x in the following two equations,

x/2 = pi/4

and

x/2 = 7pi/4

This gives us

x = pi/2

and

x = 7pi/2