### Home > PC > Chapter 6 > Lesson 6.1.2 > Problem 6-28

6-28.

Sylvie needs to solve . But when her test is returned, she finds she earned only partial credit on the problem.

What is wrong with Sylvie’s method?

There are multiple solutions.

What should Sylvie have answered to receive full credit? Explain your answer.

Sylvie needs to include all the solutions, which she can get using a graph or unit circle.

She needs to add multiples of, and include the negative values. , whereis an integer.