# Finding normal and tangent of a curve

• Oct 14th 2009, 03:38 PM
Finding normal and tangent of a curve
Ok, i generally know how to find a tangent and it's normal by applying the f(a+h)+f(a)/h formula, but this equation apparently has tan(trig) and I have no idea how to deal with it:
y=2tan(pix/4) at x =1
• Oct 14th 2009, 03:50 PM
skeeter
Quote:

$\frac{d}{dx} \tan{u} = \sec^2{u} \cdot \frac{du}{dx}$