I do not understand the question. But you need to take the limit, because subsitutiing that value at that point is just not define.
Post #1
Hey, guys. I'm new to the whole calculus branch of mathematics (we've just started) and I'm utterly confused about some concepts. Initially, we had started working finding the slope of a tangent to a particular point on a curve via m= f(a+h)-(a)/ h and working it by subbing in the given point etc... now in another chapter, the equation for calculating the derivative function is given, f ' (x) = lim h-->0 f(x+h)-f(x)/ h .. I'm curios to know what's the difference.. just the a is replace by a different variable.
Now when you plug in x=2 you get
This is the gradient of both the curve and the tangent line at x = 2. However, the tangent line has a constant gradient, so you have
as the equation of the tangent line.
From , plugging in you get (finding this y coordinate [which is on the tangent line as well] gives us enough info to complete the equation)
=>
=>