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# C2 help needed Watch

1. Given that y=5x^2 + ax + b has a turning point at (b,a) ( a cannot =0)
find a and b

I differentiated to get 10x+a, but don't know where to go from here.
2. (Original post by Vorsah)
Given that y=5x^2 + ax + b has a turning point at (b,a) ( a cannot =0)
find a and b

I differentiated to get 10x+a, but don't know where to go from here.
If y=f(x) has a turning point at x=b then dy/dx = 0 at x=b.

So set your derivative to 0 and solve.
3. (Original post by Vorsah)
Given that y=5x^2 + ax + b has a turning point at (b,a) ( a cannot =0)
find a and b

I differentiated to get 10x+a, but don't know where to go from here.
set that =0
4. If it's the turning point, the derivative must be 0.

So set 10x + a = 0, and solve.

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Updated: April 9, 2013
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