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confusedbuzz
Apr 5, 2008, 07:10 AM
I had to do this question :

The function f is defined for the domain -3≤ x ≤3
Find the range of f



I know we're not supposed to just copy questions we are supposed to do but I tried this and I kept getting the answer 53 ≤ x ≤ 89 which is apparently wrong

what I did was insert -3 into the function first and get 89 as one end of the domain and then insert 3 into the function and get 53 and I just rotated them around from

89 ≤ x ≤ 53
to
53 ≤ x ≤ 89

anyway, that's not the answer I'm supposed to get

can anyone help? Thanks

galactus
Apr 5, 2008, 12:11 PM
What's the function?

confusedbuzz
Apr 5, 2008, 12:19 PM
Oh sorry I forgot that

f(x) = 9(x-1/3)^2 - 11

galactus
Apr 5, 2008, 12:37 PM
Look at the graph. The lowest point occurs at x=1/3(the vertex of the parabola) and the highest occurs at x=-3

The domain is what you put in, the range is what comes out. -3 and 3 won't necessarily give the minimum or maximum.