You know the period of the cos function is <span>2π</span>, right? Every <span>2π</span> that the argument to cos goes through is one complete cycle. You've multiplied the argument by <span><span>2π</span>3</span> so that changes the period. If we had simply multiplied by 2, you would have 2 cycles per <span>2π</span> change in θ instead of the usual 1, and the period would be correspondingly halved. Can you figure out the new period in your equation?
The amplitude is easy to find. The value of cos<span> varies from 1 to -1. You've multiplied it by 1/4. What will that do to the amplitude?</span>
A)Add 3 and the continue to add 2 more to three each time to get the next number B)add 1 and add one to the number one each time to get the the next number