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anonymous

  • 4 years ago

How can you find the intervals on which f is increasing and decreasing when f(x)=(x^4)-(4x^3)+(4x^2)

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  1. IsTim
    • 4 years ago
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    Solve for x I guess. You know how to do that, right? Then, you make a chart with the data...

  2. anonymous
    • 4 years ago
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    all i did so far was find the derivative and replaced f(x) with 0

  3. anonymous
    • 4 years ago
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    and found x= 0, 5, and -1

  4. IsTim
    • 4 years ago
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    Ok. Those will be your interval points. They go: (infinity,o)(0,5) and (5,-1)

  5. IsTim
    • 4 years ago
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    To find the y-int, sub in x=0

  6. anonymous
    • 4 years ago
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    what do you mean?

  7. IsTim
    • 4 years ago
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    |dw:1327657008314:dw| I mean that you make x=0 to for the y-intercept.

  8. anonymous
    • 4 years ago
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    After you find the derivative equate it to 0 and solve for x, then substitute the 3 values you get into the given function. Now if it is negative,it has a max at that point and is therefore going to decrease in that interval whilst if it is positive it is a min and therefore it is going to increase in that interval.

  9. anonymous
    • 4 years ago
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    http://www.wolframalpha.com/input/?i=f%28x%29%3D%28x%5E4%29-%284x%5E3%29%2B%284x%5E2%29

  10. campbell_st
    • 4 years ago
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    I'd graph the curve find the zeros, x=0, 2 are the zeros.... found by factorising next find the 1st derivative..... and find the stationary points... next find the 2nd derivative and any possible points of inflexion.... test the 1st derivative points in the 2nd derivative to test concavity... draw the graphs... and read the intervals off...

  11. anonymous
    • 4 years ago
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    i got it, thanks everyone

  12. IsTim
    • 4 years ago
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    Good work everyone. BATMAN AWAY

  13. anonymous
    • 4 years ago
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    lol

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