- #1
wiz0r
- 57
- 0
Hello, I got the following problem;
Find the min and max of the following function, on the following interval;
f(x) = x^3 - 6x^2 + 9x + 15, [0, 5]
Ok, to my knowledge, what I need to do is
I: Find the first derivative and equal it to zero, so;
f'(x) = 3x^2 - 12x + 9
0 = 3x^2 - 12x + 9
x = {1, 3}
II: Now, I find the second derivative to determine if it's a Minimum or a Maximum, so;
f''(x) = 6x - 12
f''(1) = 6(1) - 12 = -6
Since -6 < 0 it's a minimum
f''(3) = 6(3) - 12 = 6
Since 6 > 0 it's a maximun, right?
Now, what do I do with the interval?? Am I doing it wrong?
Please, help me fast, I got a test in 3 hours, and I need to know this before my test!
Thanks,
~Edwin
Find the min and max of the following function, on the following interval;
f(x) = x^3 - 6x^2 + 9x + 15, [0, 5]
Ok, to my knowledge, what I need to do is
I: Find the first derivative and equal it to zero, so;
f'(x) = 3x^2 - 12x + 9
0 = 3x^2 - 12x + 9
x = {1, 3}
II: Now, I find the second derivative to determine if it's a Minimum or a Maximum, so;
f''(x) = 6x - 12
f''(1) = 6(1) - 12 = -6
Since -6 < 0 it's a minimum
f''(3) = 6(3) - 12 = 6
Since 6 > 0 it's a maximun, right?
Now, what do I do with the interval?? Am I doing it wrong?
Please, help me fast, I got a test in 3 hours, and I need to know this before my test!
Thanks,
~Edwin