Thursday, February 11, 2010

The function f(x) from the graph f '(x)

1. f(x) is increasing at the intervals (-2,0)U(2,0)


f(x) is decreasing at the intervals (-infinti, -2)U(2, infinti)

where f '(x)>0 f is increasing & f '(x)<0function is decreasing


2. at x= +/- 1.25 local max. the slope increases then decreases so they have to be max's.


3.concave up at (-infinti, 2) concave down (2, infinti)

we know where f is increasing up and then decreasing down determining the concavities.


4.quadratic maybe end behavior of x to the power of 5.


3 comments:

  1. i saw everything differently from you. but im not sure if im right. i agree wiht number 1 but not quite number 3. i think to see whether f(x) concaves up or down.. i think we have to look at whether the slope of f '(x) is positive or negative. so i think it concaves up where the slope of f '(x) is positive and concaves down where the slope of f '(x) is negative.
    concaves up: (-∞,-1.25)U(1.25,∞)
    concaves down: (-1.25,0)U(1.25,2)

    i dont know if im right or wring!1 i still kinda confused!!!

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  2. I agree w/ Wendy. Your number 1 looks great but number 3 needs help.
    With 2, that was my fault. I was asking for the extrema of f(x), not this graph, f'(x). If I was, you are still missing the local min at x=0.
    4. No "end-behavior" here. This is strictly talking about this picture that you see. Quadratics are always to the degree of 2, not 4. 4th degrees are called quartics.

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  3. im losing it i think i lost count after some posts

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