Math Help - period of sine

1. period of sine

i know the line of 2pi and graph on it, but i dont understand any other period.

this is actually extra credit because we havent covered anything other than the 2pi line.

y=sin2x
i know the period changes from 2pi to pi. but dont understand how to graph that, or rather how to brwak up the line into equal parts.

any help is appreciated! thanks.

2. Re: period of sine

Originally Posted by noork85
i know the line of 2pi and graph on it, but i dont understand any other period.

this is actually extra credit because we havent covered anything other than the 2pi line.

y=sin2x
i know the period changes from 2pi to pi. but dont understand how to graph that, or rather how to brwak up the line into equal parts.

any help is appreciated! thanks.
Break up what line? There sine curve is not a line...

3. Re: period of sine

sorry, ur right. i meant dividing the period interval. is that correct?

4. Re: period of sine

From 2pi to pi is where you get confused

5. Re: period of sine

Yeh, im sort of lost as to how to divide the line.

Like for instant -3cos1/2 iknow -3 is the amplitude and the period would be 4pi, but i dont know when i construct the graph what my labeling points would be. This is supposed to be the easy part but its got me stuck. i had one on my final and i didnt know how to label so i got points taken off for that. I just did it on my calc and drew the graph and labellednthe 5 key points. But didnt know what to write on the labels. Pi, 2pi, 3pi/2....do u understand what i mean?

6. Re: period of sine

Like for instant -3cos1/2 iknow -3 is the amplitude and the period would be 4pi, but i dont know when i construct the graph what my labeling points would be.
I'm assuming you meant ...

$y = -3\cos\left(\frac{x}{2}\right)$

... a standard cosine curve reflected over the x-axis, stretched from $0$ to $4\pi$.

$(0,-3) , (\pi,0) , (2\pi,3) , (3\pi,0) , (4\pi, -3)$