Posted by **Roger** on Tuesday, September 20, 2011 at 8:43am.

Suppose the function G(t) represents a test grade (out of 100 points) as a function of hours studied. If

G(t)=-0.046t^3+0.915t^2+38.005 points, what is (dG/dt)when t=4? Round your answer to the nearest point per hour.

a. 50 points per hour

b. 3 points per hour

c. 5 points per hour

d. 7 points per hour

e. 20 points per hour

- calculus -
**Writeacher**, Tuesday, September 20, 2011 at 8:48am
Your umpteen posts have been removed.

Once you write up **WHAT YOU THINK**, please re-post, and someone here will be happy to comment.

- calculus -
**Roger**, Tuesday, September 20, 2011 at 8:52am
WHY ARE YOU DELETING MY POSTS?

- calculus -
**Writeacher**, Tuesday, September 20, 2011 at 9:00am
To quote one of our very good math and science tutors: **"You will find here at Jiskha that long series of questions, posted with no evidence of effort or thought by the person posting, will not be answered. We will gladly respond to your future questions in which **__your thoughts__ are included."

- calculus -
**Anonymous**, Tuesday, September 20, 2011 at 9:14am
Derivative of t ^ 3 = 3 * t ^ 2

Derivative of t ^ 2 = 2 * t

Derivative of 38.005 = 0

dG / dt = - 0.046 * 3 * t ^ 2 + 0.915 * 2 t + 0 = - 0.138 * t ^ 2 + 1.83 * t

When t = 4

then :

dG / dt = - 0.138 * 4 ^ 2 + 1.83 * 4

dG / dt = - 0.138 * 16 + 7 . 32

dG / dt = - 2.208 + 7.32

dG / dt = 5.112

Rounded to the nearest point per hour :

dG / dt = 5 points per hour

## Answer This Question

## Related Questions

- Math - The table below represents the velocity of a car as a function of time: ...
- Pre Calculus HELP!? - The length of a day in Philadelphia, Pennsylvania, is ...
- Pre-Calculus - I'm having trouble with this question. The number of horse-power ...
- Math - Manny is a plumber and charges $50 when he visits a client and $30 per ...
- Math - Jeremy uses the linear function G=12h+50 to represent the grade, G (in ...
- Algebra - x -1 -1 -2 -2 y 0 -1 2 3Part A: Does the table represent a relation ...
- math - Part A: Does the table represent a relation that is a function? Justify ...
- Statistics - The accompanying data show the number of hours, x, studied for an ...
- math - Please help me with this problem: Jhon missed 5 points out of 100 points ...
- Pre-Calculus HELP!! - The length of a day in Philadelphia, Pennsylvania, is ...

More Related Questions