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anonymous

  • one year ago

Math

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  1. ybarrap
    • one year ago
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    Set f'(x)=0 and find those values of x that are in this interval $$ f'(x)=3 (x-3) (x+1) $$ Validate that derivative. Set it equal to zero. What do you get? Always plot it. http://www.wolframalpha.com/input/?i=+x%5E3+%E2%80%93+3x%5E2+%E2%80%93+9x+%2B+2 You can see that this extrema where f'(x)=0 is actually a minimum. So You will need to check the endpoints. Which is larger?

  2. anonymous
    • one year ago
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    When I set it equal to 0 I get 3 and 1.

  3. ybarrap
    • one year ago
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    Check that the points you get are in the interval [0,6]. You will find, by using the second derivative test, and simply looking at the graph above, that this point is actually a minimum. So now you'll need to look at the endpoints.

  4. ybarrap
    • one year ago
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    Is f(0) > f(6)? These are the endpoints Whichever value of x that makes f(x) larger is you maximum, because f'(x) is a minimum. I hope you see this.

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