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February 14th, 2017, 11:54 PM   #1
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Solve using phasors and express it in time domain

Perform the following using addition using phasors
(a) V = 40sin2t + 60cos(3t-45 degree)

How do I solve it if the angular frequency is difference?

The youtube video teaches only if the angular frequency is the same
For example , this link
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February 15th, 2017, 05:39 AM   #2
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You can't really apply phasors to sinusoids of different frequencies. Their phase difference is time varying.

are you sure that the second frequency shouldn't be $2t - 45^\circ ?$
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February 15th, 2017, 10:12 PM   #3
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Quote:
Originally Posted by romsek View Post
You can't really apply phasors to sinusoids of different frequencies. Their phase difference is time varying.

are you sure that the second frequency shouldn't be $2t - 45^\circ ?$
Ya. is it possible to add them together if use other method?
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February 16th, 2017, 06:39 AM   #4
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Quote:
Originally Posted by KaiL View Post
Ya. is it possible to add them together if use other method?
the method usually used is

$\cos(a)\cos(b) =\dfrac 1 2 ( \cos(a+b) + \cos(a-b))$

This gets you the standard 2x frequency, (a+b), which is usually filtered out, and the "beat frequency", (a-b), which you're familiar with if you've ever tuned a guitar.
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