# Math Help - Problem #5 Final Calculus I Exam Spring 2007

1. ## Problem #5 Final Calculus I Exam Spring 2007

Re:

2. Hello, qbkr21!

Absolutely correct . . . good work!

3. Originally Posted by qbkr21
Re:
What is going on in the attachment?

You are differentiating:

d^2 = 10x^2 + 14x + 7

with respect to x, which should give:

2d (d/dx)(d) = 20x^2 +14

so if (d/dx)(d) = 0 as we need for a stationary point you have:

20x^2 +14 = 0

which is what you have, but how did you get there?

RonL