anonymous one year ago 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. C. What is the equation of the midline? What does is represent?

1. anonymous

$y=\frac{ 1 }{ 4} \cos \frac{ 2\pi }{ 3 }$theta

2. kropot72

In the equation $\large y=A \cos(Bx)$ the period T is given by $\large T=\frac{2\pi}{B}$ and the amplitude is absolute value of A = |A| You need to plug the values into the above to find the values of the period and the amplitude.

3. kropot72

In your equation $\large B=\frac{2\pi}{3}$ and |A| = 1/4

4. anonymous

So the period is T= 2pi/3 and the amplitude is 1/4?

5. kropot72

The amplitude is 1/4. The period is given by $\large T=\frac{2\pi}{\frac{2\pi}{3}}$

6. anonymous

So that's the period, the amplitude is 1/4. How do we find the midline cuz i have to show my work

7. kropot72

$\large T=\frac{2\pi}{\frac{2\pi}{3}}=\frac{2\pi}{1}\times\frac{3}{2\pi}=?$

8. anonymous

3?

9. kropot72

Correct, the period is 3 units. There is no y-shift, therefore the equation of the midline is y = 0

10. kropot72

The equation y = 0 is simply the x-axis.

11. anonymous

How do we find the midline though? @kropot72

12. anonymous

@UsukiDoll

13. anonymous

@Astrophysics

14. kropot72

As I posted previously "There is no y-shift, therefore the equation of the midline is y = 0" "The equation y = 0 is simply the x-axis."

15. kropot72

|dw:1437193916695:dw|

16. kropot72

@EllenJaz17 Do you need more explanation?

17. anonymous

No thank you so much, sorry i was writing everything down

18. anonymous

Once again thank you so much for your help, I gave you a medal

19. kropot72

You're welcome :)

20. anonymous

I hate trig

21. anonymous

Yeah and this is supposed to be an Algebra class

22. anonymous

That's stupid i didn't learn that crap until last year in pre-cal/trig