Find the maximum or minimum value of the function.
f(x) = 9 − x − 1/2x^2
Rewrite as
f(x) = -(1/2)x^2 - x + 9
This is a parabola that opens downward . so it will have only a maximum. If you haven't had calculus, the x coordinate of the max is given by -b/2a, where b = -1 and a = -1/2 ....So we have...
x = -(-1)/2(-1/2) = 1/-1 = -1
Now, to find the y coordinate, we just substitute for x in the function. So we have...
(-1/2)(-1)^2 - (-1) + 9 = (-1/2) + 1 + 9 = 9.5
So the max occurs at (-1, 9.5) .... Here's the graph
f(x) = 9 − x − 1/2x^2
Rewrite as
f(x) = -(1/2)x^2 - x + 9
This is a parabola that opens downward . so it will have only a maximum. If you haven't had calculus, the x coordinate of the max is given by -b/2a, where b = -1 and a = -1/2 ....So we have...
x = -(-1)/2(-1/2) = 1/-1 = -1
Now, to find the y coordinate, we just substitute for x in the function. So we have...
(-1/2)(-1)^2 - (-1) + 9 = (-1/2) + 1 + 9 = 9.5
So the max occurs at (-1, 9.5) .... Here's the graph