Explain Review Testmargomi Carrasco Google Chrome nvellum Se

Explain

Review Test-margomi Carrasco Google Chrome nvellum Secure https://www.mathxl.com/Student/Player Test.aspx?TestResultid-654 College Trigonomet Review Quiz: Chapter 1 Review Qu Score: 0 of 1 pt 2 of 12 1.6.5 Find the exact value of cos , given that sin -8 and is in quadrant lV. /39 cos = (simplify ini, 1nswer.Tune an exact answer, using radicals as needed.) You arfwered 129 Question is complete Tap on the red indicators to see incorrect answers. arch

Solution

Solution:

Given sin = -5/8,   cos = ?

Use the trignometric identity cos(x) = Sqrt(1 - sin²(x))

So

cos = Sqrt(1 - (-5/8)²)

         = Sqrt(1 - 25/64)

         = Sqrt(39/64) = Sqrt(39) / 8

Cos is positive in IV^th Quadrant, so

Cos() = Sqrt(39) / 8