What is the value of \(1 - 2\sin^2 45°\)?
Answer: B
This is the cosine double angle formula, \(\cos(2A) = 1 - 2\sin^2 A\). With A = 45°, the expression is \(\cos(2 \times 45°) = \cos(90°) = 0\).
Alternatively, \(\sin 45° = \frac{1}{\sqrt{2}}\). So, \(1 - 2(\frac{1}{\sqrt{2}})^2 = 1 - 2(\frac{1}{2}) = 1 - 1 = 0\).