standard_description: Prove the Pythagorean identity sin^(2)(θ) + cos^(2)(θ) = 1 and use it to find sin(θ), cos(θ),or tan(θ) given sin(θ), cos(θ), or tan(θ) and the quadrant of the angle.
problem_activity: Task
A cup of hot coffee will, over time, cool down to room temperature.  The
principle of physics governing the process is Newton's Law of Cooling.
Experiments with a covered cup of coffee show that the temperature (in
degrees Fahrenheit) of the coffee can be modelled by the following
equation
$$
f(t) =  110e^{-0.08t}+75.
$$
Here the time $t$ is measured in minutes after the coffee was poured into
the cup.
Explain, using the structure of the expression $110e^{-0.08t} + 75$,
why the coffee temperature decreases as time elapses.
What is the temperature of the coffee at the beginning of the experiment?
After how many minutes is the coffee $140$ degrees?
After how many minutes is the coffee $100$ degrees?


aligns: no