The temperature of a liquid during an experiment can be modeled by the function f(x)=3.8cos(πx20)+2.2 , where f(x) is the temperature in °C and x is the number of minutes into the experiment.

Question

What is the lowest temperature the liquid reached during the experiment?

Round to the nearest tenth of a degree if needed.

Use 3.14 for π .

confused please help!!

Answer 1

since the lowest value of cos(x) is -1. the lowest temperature is

3.8(-1)+2.2 = -1.6