1. ## Y=ASin(bt+c)+D

The weather in Greens County in July is very regular. It varies from a low of 58 F at 4:00 AM to a high of 88 F at 4:00 PM. Find a formula that gives their temperature in terms of hours after 4:00 AM.

I got Y=15sin(Pie/12t + c) + 73 so far.
But how do I find c? What is c?

2. Originally Posted by zweevu
The weather in Greens County in July is very regular. It varies from a low of 58 F at 4:00 AM to a high of 88 F at 4:00 PM. Find a formula that gives their temperature in terms of hours after 4:00 AM.

I got Y=15sin(Pie/12t + c) + 73 so far.
But how do I find c? What is c?

c is going to depend on the starting value. If you choose midnight to be your starting value sub in point (t,Y) = (4:00AM,58) = (4,58) and solve for c.

$58=15sin(\frac{\pi}{12}(0) + c) + 73$

$-15=15sin(\frac{\pi}{12}(0) + c)$

$-1=sin(\frac{\pi}{12}(0) + c)$

$c = \frac{2\pi}{3}$