That's the product rule, not the chain rule.
If x=1, then the slope at that point is
Now, use your given points in y=mx+b to find the line equation.
The equation is with the point
I used the chain rule (I hope I used it correctly)
,
,
The problem is I don't know how to find the equation for the tangent line to the curve at the given point.
Okay, so you have the slope of the tangent line at the point where x = 1. What is the y value of this point?
Thus the tangent line at x = 1 has a slope of and touches the curve at the point . (There are a couple of 1/e's floating around. Make sure you keep track of them.)
So your line equation, becomes
at the point .
Plug this x and value into the line equation and solve for b.
-Dan