Question

Find f '(−3), if f(x) = (2x^2 − 7x)(−x^2 − 7). Round your answer to the nearest integer.

Answer 1

[1] Expand
[2] Differentiate term by term with the power rule
[3] Plug in x=3

this will get you \(f'(3)\).

Answer 2

Or, alternatively you can:

[1] Differentiate using the product rule
[2] Plug in x=3

and this as well wll get you \(f'(3)\).

Answer 3

−8x^3+21x^2−28x+49

Answer 4

Yes, the derivative is right

Answer 5

Now, plug in x=3 into that

Answer 6

ok i got -62

Answer 7

http://www.wolframalpha.com/input/?i=%E2%88%928%283%29%5E3%2B21%283%29%5E2%E2%88%9228%283%29%2B49

Answer 8

oh ok thank you!

Answer 9

YW

Answer 10

wonder why it says "round"
you are putting an integer in to a polynomial, it would be a miracle if it was a fraction or sommat

Answer 11

yeah -62 was actaully wrong

Answer 12

Oh, f`(-3), not 3.
f`(-3)=-8(-3)^3+21(-3)^2-28(-3)+49 = 538

Answer 13

This is what I get

Answer 14

ahhh ok thanks