Title: Analisi / trigonometria

seno e coseno per gli angoli 30, 60, 90

Formule \(\sin (\alpha+\beta),\sin (\alpha-\beta),\cos (\alpha+\beta) ,\cos (\alpha-\beta)\)

Q: \(\cos (2 \alpha)\)
A: \(cos (2 \alpha) = \cos^2(x)-\sin^2(x)\)
\(cos (2 \alpha) = \cos^2(x)-\sin^2(x)\)

Q: \(\cos^2 \alpha\)
A: \(\cos^2 \alpha = \frac{1+\cos (2\alpha)}{2}\)