## FreeTrader 3 years ago Given the expression 3sin(2x-pi), how would I go about determining the phase angle?

1. elica85

does it have to do with physics-oscillation?

This is a homework problem, in which I am given a list of parameters including phase angle, and told to determine those parameters, then sketch the graph of the expression.

Phase angle was not covered in lecture or recitation. As best I can recall, I have never been asked to determine phase angle of a sine function, even back in trig, and do not know how to go about that. Any help would be appreciated.

4. elica85

hm the only time i had to solve for phase angle was in physics finding it by using the equation $x(t)=Acos(\omega(t)+\phi)$ which will give you the position of a mass attached to a spring at time t. however, it turns into a sine function when determining the velocity by differentiating so $x'(t)=-A \omega \sin(\omega(t)+\phi)$

5. elica85

A was amplitude (max displacement)

6. MissPacGirl

7. elica85

yes

I believe the amplitude is 3, the period is pi, and the phase shift would be pi/2 to the right. The solution sheet for this problem says the phase angle is pi/2, so maybe phase angle is synonymous with phase shift.

9. elica85

that's what i was thinking except i thought pi would be the phase angle. how did you get pi/2?