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Idealist
Find all points of inflection: f(x)=(1/12)x^4-2x^2+15. I know that f"(x)=x^2-4 but what to do after that? Is (2, 0), (-2, 0) the answer?
to get the x-coordinate of the point of inflection, set the 2nd derivative to zero, and solve x. whatever x you get, sub it in f(x) to give you the y-coordinate.