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Math Help - increasing and decreasing functions

  1. #1
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    increasing and decreasing functions

    For the function f(x)=sin(x)+cos(x) on the interval (0, 2pi) I am supposed to find where f(x) is increasing or decreasing. I took the derivative of the function and came up with f'(x) = cos(x)-sin(x) which i set equal to zero, what do I need to do next?
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  2. #2
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    Quote Originally Posted by sydewayzlocc View Post
    For the function f(x)=sin(x)+cos(x) on the interval (0, 2pi) I am supposed to find where f(x) is increasing or decreasing. I took the derivative of the function, what do I need to do next?
    It's increasing when f'(x) > 0 and decreasing when f'(x) < 0.
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  3. #3
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    Quote Originally Posted by Prove It View Post
    It's increasing when f'(x) > 0 and decreasing when f'(x) < 0.
    Don't I need to find the critical numbers and make a table
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  4. #4
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    Do that and then use what Prove It said.
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