Problem:
Given the function
y = f(x) = sin(x)

draw the graphs of the functions y = f(x), y = f(2x), and y = f(x/2).

Visualization:
Using Maple:

> f:= x -> sin(x);

f:= sin

> plot({f(x),f(x/2),f(2*x)},x=-2*Pi..2*Pi);