First of all, why is this in the Engineering homework section?
Secondly, did you read the link you posted? You ask what the plot looks like when you multiply the sin function by 2 and when you add 2 to the sin function.
Do you know what the basic format of the sin fuction is? it is:
[tex]f(\theta) = Asin(\theta)[/tex]
"A" is the amplitude of the function and is a MULTIPLIER. So what happens to the amplitude of the sin wave when you change the value of A?
To give you a hint as to the addition problem, think of the sin function like this: When you graph the plain sin function, the waveform starts and ends at the horizontal axis, right? In that case the function could be written as [tex]f(\theta) = 0 + Asin(\theta)[/tex]
Now, what do you think that changing the 0 to a 2 does?