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ChrisV
Find the absolute extrema of the function on the closed interval. 2x + 5 cos x, [0,2pi]
Take the derivative, set it equal to zero, then take that point and plug it into the second derivative which will tell you if it is a max or min. Max if it is negative and min if it is positive. Then, take the point and plug it into the main equation for the other point.
also, because this is a closed interval, you need to evaluate at the endpoints then compare...