Thursday
March 23, 2017

Post a New Question

Posted by on Saturday, July 23, 2011 at 12:19pm.

Which of the following is a solution to the trigonometric equation
2cos2 x - 5cos x + 2 = 0?

A) 240 degrees
B) 135 degrees
C) 270 degrees
D) 90 degrees

  • Math - , Saturday, July 23, 2011 at 12:42pm

    I will read that as
    2cos^2 x - 5cos x + 2 = 0
    (2cosx - 1)(cosx - 2) = 0
    cosx = 1/2 or cosx = 2, the last part of course is not possible

    so cosx = 1/2
    x = 60° or 300°

    So none of your choices work.
    Both of my answers work in the original equation.
    Check your typing

Answer This Question

First Name:
School Subject:
Answer:

Related Questions

More Related Questions

Post a New Question