Question

f(x)=2x^2+10x, a=3.

Find the equation of the tangent line, (I am guessing based on this equation: y-f(a)=f'(a)(x-a) where a=3) Therefore: y-f(3)=f'(3)(x-3). Then the first derivative would be f'(x)=f(3+h)-f(3)/h

Answer 1

f'(3)=[f(3+h)-f(3)]/h