Exponential function

Question

The temperature of hot water cools from 100 degrees celcius to room temperature of 5 celcius. After 11 minutes the temperature of the water is 30.

Question I am trying to answer: Get the value of constant A to 3 decimal places.

f(t) = Ae^-kt +B

How do I answer this?

Answer 1

Hi Jonathan E.,

You work out the answer by writing expressions using time (t) in minutes, f(t)= temperature in .degrees. Celsius, for the data at t=0, t=11, and t= infinity (f(t)=5C for the last one) . Combine the equations to get those constants A, k, and B. That's 3 equations in 3 unknowns, should be a piece of cake?

-- Cheers, -- Mr. d.