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Find the coordinates of the point on the curve y=x^3-9x^2+24x whose gradient is -3. Hence find the equationi of the tangent to the curve y=x^3-9x^2+24x whose gradient is -3.
Okay, for the beginning i can get up to the differentiation of the equation but then I cant find a way to make it work because it always ends up with me doing the square root of a minus number, which isn't possible.
 Nov 4, 2012
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Differentiate the equation of the curve and equate it to -3, get the value of x from equating the dy/dx equation to -3 and substitute the value of x with the original equation to get the corresponding value of y. Then for the second question you substitute the value of the x and y into the equation y2-y1/x2- x1 where the values of x and y are the values gotten from the first solution and equate it to -3 and make it in the form of y= mx+c and that is the equation of the tangent
 Nov 5, 2012

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