Solve for $ \theta: \cos^{2} - \sin^{2} \theta = \frac{1}{2}, 0 < \theta < 90^\circ$.
Answer & explanation
Correct answer: option 3
We are given,
cos²θ - sin²θ = \(\frac{1}{2}\)
{ using, cos²θ - sin²θ = cos 2θ }
So, cos 2θ = \(\frac{1}{2}\)
{ we know, cos 60º = \(\frac{1}{2}\) }
So,
2θ = 60º
θ = 30º