Question

I need some help with this problem. I am supposed to find the difference quotient for the function.

f(x) = 3x + x^2

Answer 1

I have this formula f(x + h) - f(x) over h. So I'm not sure how I'm supposed to set this up?

Answer 2

You already have the function, so you need to find f(x+h). To me it looks like it might be\[f(x) = 3(x+h) + (x+h)^2=3x+3h+x^2+2hx+h^2\]\[=x^2+(3+2h)x+3h+h^2\]

Answer 3

Error in entry above. The evaluation is for f(x+h), not f(x).

Answer 4

Now you put it into the formula, and simplify.