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HallsofIvy
#3
Nov28-11, 06:58 AM
Math
Emeritus
Sci Advisor
Thanks
PF Gold
P: 39,567
You are aware that [itex]x^2/x= x[/itex] aren't you?

[itex]y= x^2/ln(x)[/itex]: [itex]y'= (2xln(x)- x)/(ln(x))^2= 0[/itex]
Use parentheses! What you wrote was [itex]y'= 2x ln(x)- (x/(ln(x))^2)= 0[/itex].

Multiply both sides of the equation by [itex](ln(x))^2[/itex]
and you are left with 2x ln(x)- x= x(2ln(x)- 1)= 0. Can you solve that?