options: Choose trigonometric functions to model periodic phenomena with specified amplitude, frequency, and midline.

Understand that restricting a trigonometric function to a domain on which it is always increasing or always decreasing allows its inverse to be constructed.

Use inverse functions to solve trigonometric equations that arise in modeling contexts; evaluate the solutions using technology, and interpret them in terms of the context.
problem_activity: Problem 1
The average monthly temperature, in degrees Celsius, in a coastal city in the United States is periodic and can be modeled with the equation
$${y=-8\mathrm{cos}\left((x-1)\left(\pi\over6\right)\right)+17.5}$$
, where
$$x$$
represents the month,
$$x=1$$
represents January, and
$$y$$
represents the average temperature in degrees Celsius.
Below is the graph of the equation.
[IMG]
A tourist wants to visit the city when the average temperature is closest to 25℃. What recommendations would you make regarding when the tourist should travel?
Problem 2
Do the activity
Burning Daylight
by Desmos. Skip slides 6 and 7.


correct_option_index: 2