i have;

$\displaystyle \frac{(sec^2x - tan x)}{e^x}$, how do i calulate this to get 0.46??? if $\displaystyle x = \pi/4$

using; $\displaystyle \displaystyle \sec{x} = \frac{1}{\cos{x}}$;

$\displaystyle \frac{( \frac{(2)}{cos 2x +1} - tan x)}{e^x}$ whats next?