Question

Cos^2(41 degrees)-sin^2(41 degrees)

Answer 1

I'll use the identity
`\cos^2\left(\theta\right)-\sin^2\left(\theta\right) = \cos(2\theta)`

So,

`\cos^2\left(41^(\circ)\right)-\sin^2\left(41^(\circ)\right) = \cos\left(2*41^(\circ)\right)\\\\\cos^2\left(41^(\circ)\right)-\sin^2\left(41^(\circ)\right) = \cos\left(82^(\circ)\right)\\\\\cos^2\left(41^(\circ)\right)-\sin^2\left(41^(\circ)\right) \approx 0.139173\\\\`