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Math Help - why is the derivative of the square root of (1-x) negative?

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    why is the derivative of the square root of (1-x) negative?

    I get the derivative of the sqrt(x) as 1/(2*sqrt(x)) but for x= 1-x the derivative is -1/(2*sqrt(x)) .

    Is this because we have multiplied by the derivative of (1-x) which would be -1?

    thanks!
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    Re: why is the derivative of the square root of (1-x) negative?

    Quote Originally Posted by kingsolomonsgrave View Post
    I get the derivative of the sqrt(x) as 1/(2*sqrt(x)) but for x= 1-x the derivative is -1/(2*sqrt(x)) .

    Is this because we have multiplied by the derivative of (1-x) which would be -1?

    thanks!
    First, check the domains of your functions and their derivatives. Second, note that sqrt{1 - x} is monotonically decreasing. How would you interpret the slope of a monotonically decreasing function?

    -Dan
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