# Help on this problem

• Mar 2nd 2009, 02:57 PM
needhelp_21
Help on this problem
Write 2 equations that have a sine curve with a maximum Y value of 6 and a minimum Y value of -2 and passes through the point 3 pie/4 , 2.
• Mar 2nd 2009, 09:10 PM
mollymcf2009
Quote:

Originally Posted by needhelp_21
Write 2 equations that have a sine curve with a maximum Y value of 6 and a minimum Y value of -2 and passes through the point 3 pie/4 , 2.

For the graph of y = sin(x), this is just a shift up 2, a change in the amplitude by a factor of 4, a change in the period by a factor of 3, and shifted to the left$\displaystyle \frac{\pi}{4}$

So,

$\displaystyle y = 2 + 4sin(3x - \frac{\pi}{4})$

Can you find the other equation? Hint: It will be in terms of cos(x) (Wink)
• Mar 3rd 2009, 03:52 PM
needhelp_21
How would it be in terms of cos(x)? They are both supposed to be in terms of sin(x).
• Mar 3rd 2009, 03:59 PM
mollymcf2009
Quote:

Originally Posted by needhelp_21
How would it be in terms of cos(x)? They are both supposed to be in terms of sin(x).

The directions say that they MUST be in terms of sin(x)? Ok, well in that case, it will be the same equation except $\displaystyle 2-4sin(3x - \frac{\pi}{4})$ which is just the same graph flipped upside down.

You could impress your teacher by showing her the cos version too, as it also is valid for that criteria.
• Mar 4th 2009, 03:28 PM
needhelp_21
Yea your right. Thanks for the help.