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# Differntiation watch

1. Find the two points on the curve y=2x^3 - 5x^2 +9x -1 whos gradient is 13

I have no idea how to do this I diffrntiated to get 6x^2 -10x +9 but dunno what to do then
2. dy/dx = 13....solve it.
3. 6x^2-10x+9=13
Solve to find 2 x values
Sub both x's into original equation to find corresponding y values.
4. (Original post by jit987)
6x^2-10x+9=13
Solve to find 2 x values
Sub both x's into original equation to find corresponding y values.
Ah right thanks
5. How would i go about this would i factorise it im really tired and confused now Worked it out i was being stupid sorry
6. (Original post by hazbaz)
How would i go about this would i factorise it im really tired and confused now Worked it out i was being stupid sorry
Bring the thirteen over to the other side such that:
6x^2-10x+9=13

6x^2-10x-4=0

Then use the quadratic formula if you find that easier.
7. Or you could divide by 2:
3x^2-5x-2=0 And see if that factorises.
8. Ye i ddi it thank you . For this one A normal to the curve y=x^2 has a gradient of 2 find where it meers the curve. How would i go about this i have only just started these so ima bit stuck
9. (Original post by hazbaz)
Ye i ddi it thank you . For this one A normal to the curve y=x^2 has a gradient of 2 find where it meers the curve. How would i go about this i have only just started these so ima bit stuck
if the gradient of the normal is 2, the gradient of the tangent would be -1/2
10. Ah right ye so then i find y using that which = - 1/4

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