# the derivative function

Printable View

• September 28th 2008, 02:02 PM
vinson24
the derivative function
given that f(3)=-1 and f '(3)=5, find an equation for the tangent line to the graph of y=f(x) at x=3

no idea where to start
• September 28th 2008, 02:13 PM
civodul
There is a formula stating that the equation of the tangeant to a curve at point A (a, f(a)) is:

y-f(a)=(x-a)f'(a)

civodul
• September 28th 2008, 02:17 PM
vinson24
i know the answer is y=5x-16 but not seeing how you get to that from that equation
• September 28th 2008, 02:21 PM
11rdc11
Just plug in the values for the formula

$y - (-1) = 5(x-3)$

and then simplify