[tex](-\frac{1}{2},\frac{1}{2})[/tex]
Amplitutde:
[tex](\frac{1}{2}-(-\frac{1}{2}))=1[/tex]
Normally for sinx amplitude is 2 (1 +1). In the case when it is half sine amplitude is halved, therefore 0.5 +0.5 = 1 Paramers alpha = 2x does not matter because it only stretches the graph horizontally.