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#1 2005-11-18 04:20:40
- Lloyd W
- Guest
Trig Waves question ???
y = 15 cos (5t - ( 3pi / 2 ) )
Now I know that the amplitude is 15 (obviously)
but how do i work out the frequency and phase.???
ironicly i have the answers which are that the period (T) = 2pi/5 and the phase shift is 3pi/10 compared to y=15cos5t
but how do u do it?
please help me
#2 2005-11-18 12:04:51
- ryos
- Power Member
Offline
Re: Trig Waves question ???
Plain old cosx has a period of 2π. The variable (t) inside of cos is multiplied by 5, which compresses the period. So, the answer is 2π/5
The shift is the quantity subtracted from the variable inside cos. It seems that the shift is divided by the coefficient of t, giving 3π/10. I don't know why this is, but I just varified it with a graphing program and it's true.
El que pega primero pega dos veces.
