The temperature of a chemical reaction ranges between −10 degrees Celsius and 50 degrees Celsius. The temperature is at its lowest point when t = 0, and the reaction completes 1 cycle during a 6-hour period. What is a cosine function that models this reaction?

f(t) = −30 cos pi over 3t + 20
f(t) = −60 cos pi over 3t + 30
f(t) = 30 cos 6t + 20
f(t) = 60 cos 6t + 30

Question

The temperature of a chemical reaction ranges between −10 degrees Celsius and 50 degrees Celsius. The temperature is at its lowest point when t = 0, and the reaction completes 1 cycle during a 6-hour period. What is a cosine function that models this reaction?

f(t) = −30 cos pi over 3t + 20
 f(t) = −60 cos pi over 3t + 30
 f(t) = 30 cos 6t + 20
 f(t) = 60 cos 6t + 30

tkhunny · Answer

What is the Range of your function?

anonymous · Answer

i have no clue

tkhunny · Answer

I do not believe that.  It's in the problem statement.  What are the lowest and highest values?

anonymous · Answer

-10 and 50???

tkhunny · Answer

Perfect.  What is the middle of that range?

anonymous · Answer

ummm idk

tkhunny · Answer

Also not believable.  You have -10 and 50.  Find the average.

anonymous · Answer

how do i do that?

tkhunny · Answer

What is the average of 1 and 3?

anonymous · Answer

what is an average?

tkhunny · Answer

Okay, you are not prepared to solve this problem.  Way are you in this class?  Is this a placement exam?  If it is, you should get this one wrong so that you can be in the right class.