ok..i've open it...thanks...!!
now i'm tryng to make some graph...but it' so difficult...

i wrote three functions like the example in your websit..
y1=sin(x)
y2=cos(x)
y3=tan(x)

if i choose plot...the graph became all white..if i choose Evaluate i dunno what to do..
i've got
X=
y1=
y2=
y3=
every number i wrote on X=, i have in other form(y1,y2,y3( this message:
Error: name "sin" is no defined
Error: name "cos" is no defined
Error: name "tan" is no defined






PS. i've a good graph with rational function...