CCSS Honors 9.5 Example 5
- Walch Education
The average temperature for the city of Madison, in degrees Fahrenheit, is described by the function , where is the number of months that have elapsed since January 1. In what month will the average temperature reach 60°F? What day, approximately? Assume the year is not a leap year.
- Set up the equation to be solved.
- Isolate the trigonometric function.
- Use the appropriate inverse function to cancel out the trigonometric function.
- Evaluate the term containing the inverse trigonometric function, making sure your answer is within the range of the function.
- Expand the answer using your knowledge of reference angles and periodicity to find all possible solutions.
- Solve the results for .
- Test that the results satisfy the original equation.
- Use the results to determine when the average temperature will be 60°F.