Mathematica not plotting for me

[flyingpig]

Homework Statement

I've been trying to plot

Plot[x^2/4 - ln[x]/2, {x, 0, 5}]

And it keeps showing me a blank graph. I did it on Wolframalpha and it worked.

 

[phyzguy]

A blank graph means it didn't understand something in your expression. In this case it is ln[x], which needs to be Log[x]. Try:

Plot[x^2/4 - Log[x]/2, {x, 0, 5}]

 

[flyingpig]

thanks