# Thread: Finding normal and tangent of a curve

1. ## 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

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
are you aware of the general formula for the derivative of the tangent function ?

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

finding the value of the derivative using the limit definition is going to be a bit long and overwhelming algebra-wise.