Which cosine function has a maximum of 2, a minimum of -2, and a period of 2pi/3?

y=3cos2(theta)
y=2cos(2theta)/(3)
y=2cos3(theta)
y=2cos(theta)/(3)

Question

Which cosine function has a maximum of 2, a minimum of -2, and a period of 2pi/3?

y=3cos2(theta)
y=2cos(2theta)/(3)
y=2cos3(theta)
y=2cos(theta)/(3)

anonymous · Answer

@hartnn

anonymous · Answer

@johnweldon1993

hartnn · Answer

Amplitude = A = 2 is given

Period T = 2pi/3

use the general form of cos function : 
$\Large y = A \cos (\dfrac{2\pi}{T}\theta  )$

anonymous · Answer

So it would be 2 cos 2theta/3?

hartnn · Answer

how did you get 2theta/3 ??


2pi/T with T =2pi/3 
gives

2pi/(2pi/3) = ... ?

anonymous · Answer

I entered it into my calculator. But 2pi/2pi/3 is 3

hartnn · Answer

yes, 3 is correct!

hartnn · Answer

y=2cos3(theta)

anonymous · Answer

Ohh okay! Thank you! :) These are difficult for me. I've been practicing a little more.

hartnn · Answer

good! keep practicing :)
welcome ^_^