Monday

October 20, 2014

October 20, 2014

Posted by **Cam** on Wednesday, March 6, 2013 at 10:06pm.

- calculus -
**Reiny**, Thursday, March 7, 2013 at 9:11amf ' (x) = 3ax^2 + 12x + b

given:

f ' (-1) = 0 ----> 3a -12 + b = 0 or 3a + b = 12

f ' (2) = 0 ----> 12a + 24 + b = 0 or 12a + b = -24

subtract them:

9a = -36

a = -4

back in 3a + b = 12

-12 + b = 12

b = 24

a = -4, b = 24

check:

f ' (x) = -12x^2 + 12x + 24

= 0 for a max/min

x^2 - x - 2 = 0

(x-2)(x+1)=0

x = 2 or x = -1 , yeahhhh!

**Answer this Question**

**Related Questions**

Applied Calculus - Let f(x) = −x2 + ax + b. Determine the constants a and ...

calculus - If g is a differentiable function such that g(x) is less than 0 for ...

algebra - 1. How to find the numbers, if there are any, at which f has a ...

differentiability - If g is a differentiable function such that g(x) is less ...

Calculus - Find the relative extrema, if any, of the function. Use the second ...

Physics - A plane is flying 126 m/s east relative to the air. The wind is ...

calculus - A polynomial function p(x) has a relative maximum at (3, -4) a ...

Calculus - Use the given derivative to find all critical points of 'f' and at ...

Calculus - 3. Discuss the graph of y=x/3+2+3/x. Determine the values of x for ...

Calculus - Use the given derivative to find all critical points of 'f' and at ...