Math I'm so confused
posted by Josh on .
Find the absolute maximum and absolute minimum values, if any, of the function. (If an answer does not exist, enter DNE.)
f(x) = x2 − x − 5 on [0, 5]
Come someone please show me how to do these problems? I'm lost

Set the derivative equal to zero and see if there is a solution in that interval.
2x  1 = 0
x = 1/2
Now plot it (or take the second derivative f''(x) = 2) to see if that is a maximum or a minimum.
If you have not learned what a derivative is, complete the square of the f(x) function.
f(x) = (x  1/2)^2  5 1/16 = 0
Obviously the lowest value of f(x) is obtained at x = 1/2