`cos^2 (x) - 2cos(x) - 1 = 0, [0,pi]` Use a graphing utility to approximate the solutions (to three decimal places) of the equation in the given interval.

Textbook Question

Chapter 5, 5.3 - Problem 76 - Precalculus (3rd Edition, Ron Larson).
See all solutions for this textbook.

1 Answer | Add Yours

gsarora17's profile pic

gsarora17 | (Level 2) Associate Educator

Posted on


using quadratic formula,




Solutions for cosx=1+`sqrt(2)` : None as cos(x) can not be greater than one for real solutions.

cos(x)=1-`sqrt(2)`  , x=arccos(1-`sqrt(2)` )

See the attached graph, Approximate x=2.000

This image has been Flagged as inappropriate Click to unflag
Image (1 of 1)

We’ve answered 319,639 questions. We can answer yours, too.

Ask a question