Sine function and finding average, max values

• May 12th 2009, 12:31 PM
artichoke
Sine function and finding average, max values
I've tried every way I know and I just can't figure this out, yet I was never good at this as it was never explained throughly to me, so I really need help, I can't seem to find anything that explains the process to me of how to find average values.(Doh)

The given: A sine function y=f(x) has a period of 8 and amplitude of 3. The minimum value of the function is f(2)=-1.

Now, I need to find the average values of this function, three values of x such that f(x)=average value, the maximum value, and three values of x such that f(x)=average value.

Any help would be appreciated, maybe something will jog my memory on this! Thanks.
• May 12th 2009, 01:33 PM
e^(i*pi)
Quote:

Originally Posted by artichoke
I've tried every way I know and I just can't figure this out, yet I was never good at this as it was never explained throughly to me, so I really need help, I can't seem to find anything that explains the process to me of how to find average values.(Doh)

The given: A sine function y=f(x) has a period of 8 and amplitude of 3. The minimum value of the function is f(2)=-1.

Now, I need to find the average values of this function, three values of x such that f(x)=average value, the maximum value, and three values of x such that f(x)=average value.

Any help would be appreciated, maybe something will jog my memory on this! Thanks.

The average of a sine wave is given by using the root mean square since a sine wave has an arithmetic mean of 0:

$\displaystyle \mu_{rms} = \frac{A}{\sqrt{2}}$ where A is the amplitude

I'm not sure what the period is but you can put -1 = 3sin(2B+c) where B is the period (I think) and c is the phase angle