Question from Steve, a student:

2cos^2(X)-2sin^2(x)+1=0

Hi Steve,

2cos^{2}(x) - 2sin^{2}(x) + 1 = 0

can be written

2[cos^{2}(x) - sin^{2}(x)] = -1

Use an expression for cos(2x) and solve for x.

Harley