In these you need to check the endpoints and where f'=0.
That's rather straight forward.
So in (1) f'=0 at x=0.
So you just need to compare f(0), f(-5) and f(2).
But clearly, since this is an 'upside down' parabola the max occurs at x=0 and that value is 4.
The min occurs at the endpoints, just comapre those two.
To find minimum and maximum values you need to take the derivative and then use a sign chart to see where the sign of the derivative changes from - to + OR + to - on the given interval.
When the sign of f' changes, the graph of f will have a max or min.
Mar 3rd 2009, 05:15 PM
In 2 you can use calculus also, but it's real easy to complete the square. .
Hence the abs min occurs when x=-4 or 4, value is -251.
BUT you need to make sure these are x's in your region.
Well -4 isn't, so abs min occurs at x=4, now check for enpoints to get your max.