Question

What am I doing wrong in this tangent line approximation?

Answer 1

Okay:
f(-0.5) = 2
f'(-0.5) = 4
Need to find f(0)

The tangent line approximation formula is f(x) = f(a) + f'(a)(x - a).
So plugging in these values, I get: f(0) = 2 + 4(0 - -0.5) = 4

4 is what I get as my answer given this information, but my answer choices are only 0,1, -2, -3, or 5! What am I doing wrong? It seems like a simple problem, but I keep getting the same answer!

Answer 2

can you give me the complete function/question?

Answer 3

Any chance they give you a second derivative?

Answer 4

Or perhaps one of those given values is supposed to be negative?

Answer 5

There isn't anything else -- what I listed is everything I'm given. I mean, I know how to do the problem, but given that I keep getting an answer that's not one of my choices, I thought I must have been making some rookie mistake.
If you guys don't see me doing anything wrong, then I may just contact my instructor.

Answer 6

Yeah, that's probably wise.

Answer 7

4 is the correct answer, based on what you're given.

Answer 8

did you evaluate the derivative/function correctly?

Answer 9

I have gone over it multiple times; it is really just simply plugging in values.