Thank you I'll try

Hello,

I know, Google is my friend, but i don't find the answer to a very simple question 

How can I build a "model" (in fact it is not a model) to simulate an equation.

For exemple :
x = 0,5.a.t² in function of a.

How can I see the influence of the variation of the parameter "a" in only one graph.
I'd like to have, in one graph, the simulation for a = 5, a = 10, a = 15, a = 20

Is my question clear enought ???

Do you have a link for a documentation, a video ???

Thank you very much !
Guillaume