Any help is appreicated.
The midline of 10 rules out all of the choices except the last two.....
normal period of sin fxn is 2 pi if you divide 'x' by pi/2 you stretch the wave out by a factor of 2 /pi 2 pi * 2/pi =4
so the last one is the correct one
Pretty good....except you marked amplitude incorrectly on your drawing....it should be 1/2 of the wave height.
ahhh yes. you're right