You may want to look at the help module Graphing a function for this module.
The screen below shows the Y= screen for graphing the three functions
y = sin(x)
y = 2 sin(x)
y = 1.5 sin(x)
The style for this first graph has been set to thick; for the second graph to line; and for the third graph to dot as described in the help module Graphing a function
The resulting graphs are shown below.