## heathernelly 3 years ago kkkkk

1. dpaInc

can you give me the derivative of f ??

2. heathernelly

that's all it says :// :(

3. dpaInc

yes... but you need to calculate the derivative of f to find the relative max/min of the function.

4. dpaInc

isn't this for a calculus class?

5. heathernelly

algebra 2

6. dpaInc

oh... sorry....

7. heathernelly

its okay :) so you don't know how to do it? :(

8. heathernelly

i know how to do it on a calculater ..but i left it at a friends house ://

9. dpaInc

oh... so you're allowed to use the max/min functions of a graphing calculator?

10. heathernelly

yes

11. dpaInc

ok... hang on...

12. heathernelly

okaay :)

13. dpaInc

since you don't have your graphing calculator with you, use this online one.... https://www.desmos.com/calculator i've also included the graph of your function here:

14. dpaInc

it looks like you have a relative max at x=-4 and a relative min at x=0

15. heathernelly

yeah, but that's not one of my options :(

16. dpaInc

the function you gave at the start does not coincide with those choices...

17. heathernelly

thats what it says in my homework

18. dpaInc

i double checked with this function you gave at the start: \(\large f(x)=x^3+6x^2-36 \) f has a relative max at x=-4 and a relative min at x=0.

19. dpaInc

f(-4) = -4 so (-4, -4) is a relmax f(0) = -36 so (0, -36) is a relmin

20. heathernelly

but that's none of the options ://

21. dpaInc

i'm sorry.... i'm absolutely sure of my answer here.. even the calculator verifies my answer.... is this the function we started with correct?

22. heathernelly

yes it is ..hmm :// :(

23. heathernelly

im just going to pick a or b:///.. lol ..thank you for the help though :)

24. dpaInc

idk what to say... :(

25. heathernelly

do you think you could help me with another one?

26. dpaInc

there has to be an error in those choices... yw... :)

27. dpaInc

yes...

28. heathernelly

What is a cubic polynomial function in standard form with zeros 1, –2, and 2?

29. dpaInc

do you know how to multiply out binomials?

30. heathernelly

i know i have to write like (x+1)(x-2)(x+2)

31. dpaInc

standard form for a cubic polynomial is: \(\large y=ax^3+bx^2+cx+d \) where a, b, c, d are real numbers.

32. dpaInc

not quite... since the zeros are 1, -2, and 2, then the factors are (x-1)(x+2)(x-2)

33. dpaInc

so all you do is multiply out the 3 binomials....

34. heathernelly

how is it -1 when it says 1 ?

35. dpaInc

a zero refers to where the graph crosses the x-axis (when y=0) so the equation is 0 = (x-1)(x+2)(x-2) if x=1, you'll have 0 = (1-1)(1+2)(1-2) which is a true statement but if you have what you wrote down, 0 = (1+1)(1+2)(1-2) is not a true statement

36. dpaInc

multiply out the binomials: (x-1)(x+2)(x-2) = \(\large x^3-x^2-4x+4 \)

37. heathernelly

thanks :)