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    A curve with equation y=f(x) such that
    \frac{dy}{dy}= 3x to the power of half - 2x to the power of minus a half and x>0.

    a, Find the gradient of the curve at the point where x=2, giving your answers in its simplest form.
    I substituted 2 in for x to get 3 \sqrt 2 - 2\sqrt 2 = \sqrt 2.
    But, the mark scheme says that the answer is 2\sqrt 2???
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    Have another look at what you get when you substitute x=2 - your version isn't quite right. Don't forget the minus in the second power!
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    (Original post by Pangol)
    Have another look at what you get when you substitute x=2 - your version isn't quite right. Don't forget the minus in the second power!
    i keep getting the same answer! what would you say 2 to the power of -1/2 then multiplied by 2 is?
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    2 to the power of -1/2 is one over root 2, so you have 3 root 2 subtract 2 over root 2. You now have to rationalise the denominator of the second term before you can combine them.
 
 
 
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Updated: January 8, 2017
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