Sketching Complex Waveform with Equation y=100sinωt+30sin(3ωt-π/2)

[anthonyk2013]

Having some trouble with this question,

A complex wave is described by equation, y=100 sin ωt+30 sin(3ωt-∏/2)
A) on the same axis sketch and label,
1)one cycle of the fundamental waveform
2)the third harmonic
3) the complex waveform(y)

ω=2∏f
T=2∏/ω

Not sure where to start.
To sketch graph I need to find time, to get time I need frequency. Not sure how to find frequency from 100 sin ωt
as
Do I just treat ω as 2∏?

 

[BvU]

No, you treat $\omega\, t$ as the x coordinate.

 

[anthonyk2013]

No, you treat $\omega\, t$ as the x coordinate.

Ok so I have ωt, ωt/2, ωt/3 along my x-axis for my time coordinates ?

 

[BvU]

No, just $\omega \, t$

 

[BvU]

If you still feel uncomfortable, choose $\omega = 1$, make the y, t plot and then rename the t axis to $\omega t$ axis !

 

[anthonyk2013]

If you still feel uncomfortable, choose $\omega = 1$, make the y, t plot and then rename the t axis to $\omega t$ axis !

Where I'm getting confused is I'm used to solving the likes of 100 sin (100 ∏ t)

from there you get time=20ms, so you can plot the time axis up to 20ms.

I don't understand how to plot ωt

 

[BvU]

Perhaps I confused you earlier on, sorry. There is no solving involved, just plotting. One period in A1 -- so from $100 \, \omega\, t=0$ to $100\, \omega\, t=2\pi$

 

[anthonyk2013]

I understand now cheers.