How Do Phase Shifts Affect Resultant Wave Amplitude and Frequency?

[Husker70]

Homework Statement

Two traveling sinusoidal waves are described by the wave functions
y1 = (5.00m) sin[pie(4.00x - 1 200t)]
y2 = (5.00m) sin[pie(4.00x - 1 200t -0.250y)]
where x, y1, and y2 are in meters and t is in seconds.
(a) What s the amplitude of the resultant wave?
(b) What is the frequency of the resultant wave?

Homework Equations

y = (2Acos Phi/2) sin(kx- wt + Phi/2)

The Attempt at a Solution

The two waves are out of phase by 0.250
therefore A = (2A cos Phi/2)
I get the Amplitude to be 9.99 or 10m
from 2 (5.00m) .25/2
Do I need to do more for this? I know the answer but can't get there
Thanks,
Kevin

 

[Redbelly98]

Homework Statement

Two traveling sinusoidal waves are described by the wave functions
y1 = (5.00m) sin[pie(4.00x - 1 200t)]
y2 = (5.00m) sin[pie(4.00x - 1 200t -0.250y)]
where x, y1, and y2 are in meters and t is in seconds.

Is it "-0.250y" or just "-0.250" for the phase in y2?

(a) What s the amplitude of the resultant wave?
(b) What is the frequency of the resultant wave?

Homework Equations

y = (2Acos Phi/2) sin(kx- wt + Phi/2)

The Attempt at a Solution

The two waves are out of phase by 0.250
therefore A = (2A cos Phi/2)
I get the Amplitude to be 9.99 or 10m

It should be slightly lower. Was your calculator in radians mode when you calculated cos(0.25)?

from 2 (5.00m) .25/2
Do I need to do more for this? I know the answer but can't get there
Thanks,
Kevin