Let g be a function that is defined for all x, x ≠ 2, such that g(3) = 4 and the derivative of g is g′(x)=(x^2–16)/(x−2) with x ≠ 2.

Find all values of x where the graph of g has a critical value.

For each critical value, state whether the graph of g has a local maximum, local minimum or neither.

1 answer

since g'=0 when x = ±4, those are the only two possibilities.

g' does not exist when x=2, but that does not matter here.

Since g" > 0 at both points, both are minima.

See the graph at

http://www.wolframalpha.com/input/?i=integral+%28x%5E2%E2%80%9316%29%2F%28x%E2%88%922%29+dx