[list=1][*]Add sliders for [b]a[/b], [b]b[/b], [b]c[/b] and [b]d[/b][/*][*]In the input bar enter: [b]M={{a,c},{b,d}}[/b][/*][*]Use the [b]Point [/b]tool to add a point [b]A[/b][/*][*]In the input bar enter: [b]A'=M*A[/b][/*][/list]