Method A: lim(h->0)(f(x+h)-f(x))/h Method B:lim(x->c)(f(x)-f(c))/x-c

Question

A) f(x)=3x^2+2x at x=-1

Find the slope of the tangent line to the curve at the indicated point. Find the slope using BOTH methods.

B) Write the equation of the tangent line at x=-1

Answer 1

Both methods should give you the same answer: 6x+2

At x=-1, the slope is -4, f(-1)=1 and therefore the tangent line is -4=(y-1)/(x+1)