## Trigonometry (10th Edition)

$T=45^{\circ}$
In the interval $0^{\circ}\leq T\leq90^{\circ}$, the sine and cosine functions have the same value when $T=45^{\circ}$ $\sin 45^{\circ}=\cos 45^{\circ}= \frac{\sqrt 2}{2}$