Math - Solving for Trig Equations

Solve the following equation for
0 less than and/or equal to "x" less than and/or equal to 360

cos^2x - 1 = sin^2x

cos^2x - 1 - sin^2x = 0
cos^2x - 1 - (1 - cos^2x) = 0
cos^2x - 1 - 1 + cos^2x = 0
2cos^2x - 2 = 0
(2cos^2x/2)= (-2/2)
cos^2x = -1
cosx = square root of -1

And I can't do anything with this now...what am I doing wrong?

Textbook answers:

0, 180, 360

  1. 👍 0
  2. 👎 0
  3. 👁 169
  1. On the fourth/fifth line, you erred. When you add 2 to both sides, the right side is positive, not negative.

    cos^2 x=1
    cos x= +- 1
    giving 1, 180,360

Respond to this Question

First Name

Your Response

Similar Questions

  1. Math

    1) When will the dependent variable in the equation y=√x+4-3 equal or exceed to 4? A) x > or equal to -0.17 B) x > or equal to 45 C) x > or equal to 48 D) x > or equal to 53 2) The function t=√d/16 models the time (t) in

    asked by Tia on April 7, 2015
  2. Math

    What is the solution to the nearest tenth to the equation below? -3x -14 less than or equal to -5 * sorry if í wrote the question weird but í couldn't do some equation signs* A. X less than or equal to -3 B. X less than or equal

    asked by Anonymous on August 28, 2017
  3. Math

    Hi everyone, my name is Emerson. I was wondering if anybody could help me on a test. I'm stuck on some, but I think I know some others. Thank you! 1. Translate the phrase "nine more than two times a number" in to an algebraic

    asked by Emerson on December 7, 2015
  4. math

    7. The tennis team is selling key chains as a fundraiser. If its goal is to raise is at least 180, how many key chains must it sell at $2.25 each to meet that goal? Write and solve an inequality. a. 2.25k (greater than or equal

    asked by john on October 18, 2016
  5. math

    how would you solve for y in this problem: x=(y^2+3y)^(1/3) would it equal: y= x^3/y - 3 ? and what about this problem: x= 1/[(y^2+3y-5)^3] would it equal: y = y/x + 5/y - 3? I would appreciate your help very much! Your equation

    asked by kristie on June 27, 2006
  6. Trigonometry

    Hi, I really need help in understanding how to solve trig equations. How do you solve this equation? Solve the equation on the interval 0 < or equal to x < or equal to 2pi. sinx = (square root of 3)/2 I appreciate your help. Thank

    asked by Leah on March 17, 2013
  7. Algebra--Correction?

    Solve x^2 -3x is greater than or equal to 10 Would the solutions be x=5 and x= -2? Here's how I figured it. x^2-3x is greater than or equal to 10. I subtracted 10 from both sides. This left me with x^2-3x-10 is greater than or

    asked by Anonymous on October 13, 2009
  8. Algebra 2

    1)which of the following is equal to (2x/5 - 9)+9? a) 2x/5 b) 5x/2 c) 2x - 45/5 d) (2x - 9)+ 45 2)the equation y - 100x + 2000 can be used to represent the monthly salary of a salesman, y,when he sales x computer systems. What is

    asked by Enyce Mullins on October 18, 2017
  9. Business Math

    Using the simplex method, solve the following linear programming problem: Maximize: P= 5x+2y Subject to: 4x+3y < or equal to 30 2x-3y < or equal to 6 x > or equal to 0, y > or equal to 0.

    asked by Colleen on December 9, 2012
  10. Algebra

    I have to solve an inverse function. f(x)=x+6 and g(x)=x+6 f(x)=1/4x,x is equal to or not equal to 0 g(x)=1/4x,x is equal to or not equal to 0 Please help me I have been on this one problem for hours and I can't get it. This one

    asked by Beth on August 5, 2013
  11. Algebra

    Directions say that I have to solve and graph the equation using words.I have to include whether the lines are dotted or solid, how to graph each of them and where the solution is shaded. 2x-3y>_9 and -x-4y>_8 both should be

    asked by Erica on June 12, 2007

More Similar Questions