Find the acute angle of intersection of the curves $y=\cos x$ and $y=e^{-x}$ at the point $(0,1)$.
My method:
$y=\cos(x)$ $(0,1)$
$1=\cos(0)$
$=0$
$\frac{dy}{dx}=-\sin(x)$
$=-\sin(0)$ $=0$
I did the above step exactly from the example given in the text book, but I can't get the answer.
The answer is $45^{\circ}$
Help me out by step by step solution. thanks