You use a sine function to model the percentage of the Moon’s face that is lit by the Sun every night. At full moon, all of the Moon’s face is lit (100%). At New Moon, none of the moon’s face is lit (0%).

The output of your function expresses percentages as decimals. For example, 5% = 0.05.

What is the amplitude of your sine function?

0.1
0.5
1.0
2.0