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# C3 functions help please.. watch

1. f(X)=x(x-3), 0≤x≤3

Have to find the range.
Can someone explain step by step please
2. (Original post by Ggvvf)
f(X)=x(x-3), 0≤x≤3

Have to find the range.
Can someone explain step by step please
Start by drawing a rough sketch of the curve.

Then consider the smallest and largest values of y.
3. (Original post by notnek)
Start by drawing a rough sketch of the curve.

Then consider the smallest and largest values of y.

I've done that and managed to get one y value as 0 but how do I find the other
4. Find the turning point, which is when x = 3/2 and when x = 3/2 y = -2.25, so the range is -2.25<f(x)<0
5. (Original post by Ggvvf)
f(X)=x(x-3), 0≤x≤3

Have to find the range.
Can someone explain step by step please
It's a parabola. Find the min point and the max y values. There's your range.
6. (Original post by Ggvvf)
I've done that and managed to get one y value as 0 but how do I find the other
You need to find the minimum point of the parabola which by symmetric is halfway between the two roots (x=0, x=3).

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