Find the equation of the line tangent to y=tan2x at x=pi/8

Question

A. y-1=sqrt(2)(x-pi/8)
B. y-1=1/2(x-pi/8)
C. y-1=1/4(x-pi/8)
D. y-1=2(x-pi/8)
E. y-1=4(x-pi/8)

I got A

Answer 1

The slope is
f'(x)=d/dx(tan2x)=2sec²(2x)
so evaluate f'(pi/8) and make your choice again!