Question

what is the local maximum value of the function g(x)=x^3+5x^2-17x-21

Answer 1

I got -4.57?

Answer 2

yes thats the "x" value at which the function has a local maximum

Answer 3

you still need to find the value at x = -4.57

Answer 4

plugin x = -4.57 in given function

Answer 5

the local max happens at points f' changes the sign from positive to negative

Answer 6

how do I do that?

Answer 7

take f'

Answer 8

x = -4.57

evaluate g(x) = g(-4.57) to get the value of the local maximum

Answer 9

and do table of sign
since this is a 3 degree function you will get a parabola for f'
you need to use you knowledge about parabolas

Answer 10

How did you get that values anyway?

Answer 11

You are doing calculus right?

Answer 12

thats a good question!
if it is for precalculus, just look at the graph and eyeball it maybe..

Answer 13

look at the graph here
http://prntscr.com/5aukr4

Answer 14

if you are doing precalc you are allowed to get the max or min from grapghs

Answer 15

i got -143.15

Answer 16

look at the attached graph

Answer 17

you should get approximately `65.67 ` no matter what method you use

Answer 18

Refer to the Mathematica calculation and plot attached.