Stompy,
Do you have to use that formula for the derivative? If not, you can just take the derivative of the original formula, and once you have the slope, you can use the equation of a line "y=mx+b" and the known point (1,2) to get the equation. If you have to use the formula, apply L'Hoptal's rule (take the derivate of the top and bottom of your expression) and plug in the point. You'll get the correct slope, and then you can find the equation of the line.
__________________
You don't love me, you just love my piggy style
|