# Combining these two AC waveforms

• Engineering
• joemte

#### joemte

Homework Statement
2 AC waveforms are described by the following expressions (see equations), if V3 is the resultant combination of these waveforms find the following. Use angles as a decimal using a minus sign if appropriate.
Relevant Equations
V1 = 160sin(1800 pi t)V
V2 = 180sin(1800 pi t - pi/3)V
I have calculated V3 to be 294.62sin(1800 pi t + -0.56)V

I am confident this is correct but I now need to work out the frequency of the waveform, I believe it may be 900 but I am not too sure if my calculations are correct and I can't find anywhere on line that aids me in this particular instance.

Last edited by a moderator:

, I believe it may be 900
Yes.
Be sure to put the unit correctly.

joemte
Hi Mate, what method did you use to calculate the frequency? I'd like to compare it to mine if that is ok

Hi Mate, what method did you use to calculate the frequency? I'd like to compare it to mine if that is ok
Which method did you use?

Helpers are not allowed to give answers directly. We can only check your solution and provide clues/hints wherever required.

Ok I understand that. Are you able to give me the generic formula for working it out? I am not sure it f= 1/T applies to this question or not

What is the unit of "1800pi*t" in the expressions for V1 and V2?

From that, what is the unit of 1800*pi?