solve the equation
2cos(squared)theta=1
for 0(less than or equal to)theta(less than or equal to)2pie
(4) marks
This is wrong on three counts:
1. It's a decimal approximation to an exact value. Go back and look over your notes relating to exact values of cos for special angles ......
2. It's the wrong decimal approximation to the exact value.
3. Cosine is also positive in the fourth quadrant, so you're only considering half of the solutions to $\displaystyle \cos \theta = \frac{1}{\sqrt{2}}$.