Question

y=(-50x^3)+(10x^2)+150x+250 find the positive interval, negative interval, increasing and decreasing intervals 11:33 pm

Answer 1

To find the increasing and decreasing intervals, you have to find f'(x), which means the critcal points then make a table and plug them in , so :

x (-) 0 (+) and plug in the critical numbers
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f(x)
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f'(x)

then substitute some values of x in the original function. if you get a - answer then f'(x) is decreasing, if you get a + answer then f'(x) is increasing, and when you're done you can compute the intervals of increasing and decreasing. It would be alot easier if I show it to you by hand lol, Hope this helps ^_^

Answer 2

That sounds hard

Answer 3

LOL, believe me it's easier than you think.

Answer 4

i got f<2.36 for the positive

Answer 5

find the critical numbers, plug them in the table, then plug in some other negative numbers in the left, and positive numbers in the right. After that , plug them in f(x) to see what value we get, then write it in the f(x) row. If your answer is positive, then write in f'(x)'s row , increase and vice versa ^_^

Answer 6

it's positive, so f'(x) is increasing ^_^

Answer 7

ok what are the critical numbers

Answer 8

to know that you have to computer f'(x) :)

Answer 9

the x-intercept is 2.36 y intercept is 250 relative max is (1.06, 360.6) and relative min is (-.93, 159.36) now would you be able to tell me the intervals

Answer 10

haven't worked it out yet, but when they say positive interval and negative interval isn't it the same as finding the increasing and decreasing intervals?

Answer 11

no they are different

Answer 12

is it finding the Absolute mx and Absolute min?

Answer 13

no i don't think those exist for this equation

Answer 14

I'm still not getting what you mean by positive interval and negative interval, never heard of such thing lol >_<

Answer 15

oh. That's ok. I don't understand any of this.

Answer 16

did you understand the increasing and decreasing intervals?

Answer 17

Not really. I'll probably have to study that more.

Answer 18

after figuring out whether f'(x) is increasing or decreasing, you can then say from where and where does the function increase or decrease

Answer 19

yes!

Answer 20

oh well.

Answer 21

lol, I wish I was there to draw it for you, it'll be alot more clearer than just typing it down . I'm sorry