Chapter 2, Problem 40RE

Suppose that $f\left(x\right)=M\tan x+N\sec x$ for some constants $M$ and $N$ . If $f\left(\pi /4\right)=2$ and $f^{\prime }\left(\pi /4\right)=0$ , find an equation for the tangent line to $y=f\left(x\right)$ at $x=0$ .