# How do you find the equation of a tangent line to a curve?

##### 1 Answer

Sep 1, 2014

There is no short answer since this is a general question.

You must have a differentiable function to find a tangent line to a curve.

So, let

And let

Finally, let

#T(x)=f(a)+f'(a)(x-a)#

Note that this is also the formula for linear approximation functions.

There are many examples of tangent line and linear approximation problems, so just search for them.