# Finding Amplitude and Period

• Dec 11th 2007, 02:12 PM
Raleigh
Finding Amplitude and Period
I do not know how to solve this problem...could anyone please help me...I remember doing this somewhat, but not quite like this problem...Thank you

http://i103.photobucket.com/albums/m...1919/111_2.jpg
• Dec 11th 2007, 04:31 PM
colby2152
Quote:

Originally Posted by Raleigh
I do not know how to solve this problem...could anyone please help me...I remember doing this somewhat, but not quite like this problem...Thank you

http://i103.photobucket.com/albums/m...1919/111_2.jpg

The amplitude is basically the distance between the max and min values of the function (values of y) divided by two. Sine gets as large as 1 and as small as -1, so it's amplitude is 1. Any coefficient multiplied by sine is thus the new amplitude. In this case, the amplitude is .25 (the function is being amped by .25, in this case it is reduced by 75%)

The period deals with the x-axis, and it is the range of values it takes for the function to complete one rotation of its pattern. For sine, the function curves up then down and back up to the x-axis. Normally, the period for $\displaystyle sin(x)$ is $\displaystyle 2\pi$. In this case, x-values are divided by four, so the period would have to be four times the usual amount or $\displaystyle 8/pi$.
• Dec 11th 2007, 04:44 PM
topsquark
Quote:

Originally Posted by colby2152
\Normally, the period for $\displaystyle sin(x)$ is $\displaystyle 2/pi$. In this case, x-values are divided by four, so the period would have to be four times the usual amount or $\displaystyle 8/pi$.

There's a slight problem with the LaTeX coding here. What colby wanted to say was
"Normally, the period for $\displaystyle sin(x)$ is $\displaystyle 2 \pi$. In this case, x-values are divided by four, so the period would have to be four times the usual amount or $\displaystyle 8 \pi$."

(You used "/" instead of "\")

-Dan
• Dec 11th 2007, 04:49 PM
colby2152
Quote:

Originally Posted by topsquark
There's a slight problem with the LaTeX coding here. What colby wanted to say was
"Normally, the period for $\displaystyle sin(x)$ is $\displaystyle 2 \pi$. In this case, x-values are divided by four, so the period would have to be four times the usual amount or $\displaystyle 8 \pi$."

(You used "/" instead of "\")

-Dan

Thanks Dan, I fixed it...
• Dec 11th 2007, 07:25 PM
Raleigh
Thank you all very much!