Posted by Frank on Tuesday, March 1, 2011 at 12:45pm.
Please help with this. I submitted it below but no one responded. I need the first derivative of f(x)=4(x+ then the square root to include (x(8x)), then close bracket.And then the second derivative of this to show by the second derivative test that it is a local maximum. This is difficult to put into form here and I hope I have got it right. Many thanks.

calculus  Henry, Thursday, March 3, 2011 at 8:08pm
It is difficult to understand your Eq
because of the way it is written.You can use sqrt for square root.