I have a homework problem as follows:(adsbygoogle = window.adsbygoogle || []).push({});

If the tangent line to y = f(x) at (4,3) passes through the point (0,2), find f(4) and f'(4).

Using the slope formula and the point-slope formula, I found that the equation of the given tangent line is y = 1/4x + 2.

Now I want to find f(x) so I can actually answer the question.

I thought I might be able to solve for f(x) using the equation

f'(a)= lim [f(x+h) - f(x)]/h

h-->0

and subsituting 1/4 for f'(a), but I can't get any farther than setting that up.

help? please?

thanks!

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Given a tangent line, find f(x)

**Physics Forums | Science Articles, Homework Help, Discussion**