# How do you simplify sin(90 + x)?

Aug 14, 2015

$\sin \left(90 + x\right) = \cos x$
$\sin \left(90 + x\right) = \cos x$
Method 1: Using plots of $\sin x$ and $\cos x$. A shift of -90 degrees of $\sin x$ gives you $\cos x$
Method 2: $\sin \left(A \pm B\right) = \sin A \cos B \pm \cos A \sin B$