# How do I use the limit definition of derivative to find #f'(x)# for #f(x)=mx+b# ?

##### 1 Answer

Aug 29, 2014

Remember that the limit definition of the derivative goes like this:

So, for the posted function, we have

By multiplying out the numerator,

By cancelling out

By cancellng out

Hence,

The answer above makes sense since the derivative tells us about the slope of the tangent line to the graph of