Derivative: f(x) = 1.8x^4 - 9.1x^3 + 5x - 4

kjones

New member
Joined
Jun 1, 2006
Messages
44
f(x) = 1.8x^4 - 9.1x^3 + 5x - 4

Sketch the graph of the function, the first derivative, and the second derivative showing all relevant features.

I also need to find min and max.

Thanks,
K
 
This is a typical, straight forward question if you follow the necessary steps. What have you done so far?
 
I have entered the function into my TI-83 as a Y1 = to see the graph.

What I need help on is the first derivative and the seoncd derivative showing the features.

Can you walk me through that, please?

K
 
kjones said:
What I need help on is the first derivative and the seoncd derivative showing the features.
To differentiate polynomial terms, use the following rule:

. . . . .y = ax<sup>n</sup>

. . . . .y' = anx<sup>n-1</sup>

Use the same rule to differentiate y' to find the second derivative, y".

I don't know what your book means by "the features". Please define, showing how far you've gotten and saying where you're stuck. Thank you.

Eliz.
 
kjones said:
And I show f'(x) = 7.2x^3 - 27.3X^2 + 5 - 0

Right?

K

Correct, but drop the zero.

Set this equal to zero and solve for x to find relative maximums and minimums.
 
Top