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## mskyeg 2 years ago What is the relative maximum and minimum of the function? f(x)= x^3 + 2x^2 – 18x

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1. mskyeg

Possible answers: The relative maximum is at (3, 22), and the relative minimum is at (–2, –41). The relative maximum is at (–3, 41), and the relative minimum is at (2, –22). The relative maximum is at (3, 41), and the relative minimum is at (–2, –22). The relative maximum is at (–3, 22), and the relative minimum is at (2, –41).

2. mskyeg

I keep getting told what to do but i don't know how to do it

3. Dido525

So take the derivative.

4. campbell_st

do you know how to differentiate..?

5. Dido525

Set it equal to zero.

6. Dido525

I am assuming if he is doing this he can differentiate :O .

7. campbell_st

you will need the 1st and 2nd derivatives 1st derivative = 0 gives the stationary points 2nd derivative is used to determine the nature of the stationary points

8. campbell_st

it thats to difficult, just find a graphing package and graph the curve like geogebra http://www.geogebra.org/cms/

9. Dido525

Or a graphing calculator will do nicely...

10. mskyeg

I don't know how to do that....

11. Dido525

No calculus experience? Look like you have to use a calculator or a graphing program like @campbell_st said.

12. campbell_st

ok... do you have a graphing package...?

13. mskyeg

no i don't

14. campbell_st

ok... here is an alternative/... can you factorise the polynomial..?

15. mskyeg

um can you just show me the steps or something....I have a textbook and the instructions aren't the issue its my ability to apply it to this problem

16. campbell_st

ok... here is the easiest solution, use the table of values below,..... |dw:1352186589941:dw| substitute each x value into the graph... the largest positive y value will be the relative maximum and the largest negative y value will be the relative minimum. when you have done that, you'll find ordered pairs that match your choices...

17. mskyeg

Thanks so much:)

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