### Home > INT3 > Chapter Ch11 > Lesson 11.1.3 > Problem 11-37

11-37.

Eliana is still working hard on her senior project. She has recorded the sunset time for at least one day a month through December. Her graph of the data is shown at right. Homework Help ✎ Write a function that models the time the sun sets as a function of the week #, where June 1 is Week 1.

What time should Eliana predict the sunset to take place during the first week of March (week 41)?

One possibility is to use cosine.

Find the variables for *y* = *a*cos*b*(*x* − *c*) + *d*.

Substitute *x* = 41 into the answer from part (a).