Posted by kk on August 26, 2002 at 20:22:05:
In Reply to: sorry Mr.S. your post didn't show up until after I posted -nt- posted by T.Gracken on August 26, 2002 at 13:09:56:
thank you to the both of you for your detailed explaination. I understand how you cannot have the zero in the domain and how the negative number does not work. But how does it prove that the equation
y=(2000+20x+10x^1/2)/x cannot be minimised (i.e. the function does not have a convex). I thought we have to take the second derivative because for a convex to occur f"(x)>0.