Question

HEEELLLPPPP PLEASEEEE!
A sound wave is modeled with the equation y =1/4 cos 2pi/3 theta

a. Find the period. Explain your method.

b. Find the amplitude. Explain your method

Answer 1

note that waves can be of general eq, y=r cos wt, where r is the amplitude, w the angular velocity and t is the time parameter.

Answer 2

This looks like physics.

Answer 3

well do you know the answer?

Answer 4

Yes but just so you know. This is a physics question not mathematics.

Answer 5

cross reference your eq with the general eq above.

Answer 6

ok well can i have the answer?

Answer 7

did you try to do it yourself first?

Answer 8

yes and i am beyind confused :/

Answer 9

what did you get?
by the way, your equation didnot involve time ......

Answer 10

cause thats not what it asked for i just need the period of the graph and what the amplitude would be you do this by using trig and i got the amplitude is 4 and the period is 2 but i dont think that is right

Answer 11

\[\omega = \frac{ 2\pi }{ T }\]

Answer 12

amplitude, A
through a mathematical analysis, the amplitude is the highest/lowest point of the curve.
\(y =\frac{1}{4}\cos \frac{2\pi}{3}{ \theta}\)
\(y' =-\frac{1}{4}(\frac{2\pi}{3})\sin \frac{2\pi}{3}{ \theta}\)
let y'=0, \(\sin \frac{2\pi}{3}{ \theta}=0\)
\(\theta=0\)
y=1/4=A
you follow?

Answer 13

kinda

Answer 14

yup, now, \(y'=\omega\)
the period is the time for two wavecrest, i.e. two amplitude, also aka two y'=0
so you find the w for two successive max points and you'll get it.

Answer 15

on second thought, where is the time parameter=.=