Sunday

January 25, 2015

January 25, 2015

Posted by **Natash** on Saturday, November 22, 2008 at 9:08pm.

x1= ?

x2=?

x3=?

- trig -
**Damon**, Saturday, November 22, 2008 at 9:33pm2 (1 - cos^2 x) - cos x = 1

2 - 2 cos^2 x -cos x = 1

2 cos^2 x + cos x -1 = 0

let y = cos x

then

2 y^2 +y -1 = 0

(y+1)(2y-1) = 0

y = .5 or y = -1

so

cos x = .5 or cos x = -1

so

x = 60 degrees or 300 degrees

or 180 degrees

- trig -
**drwls**, Saturday, November 22, 2008 at 9:37pmRewrite as

2(1-cos^2x)-cosx = 1.

Rearrange as

2cos^2x + cos x -1 = 0,

which can be factored to provide:

(2cosx -1)(cosx +1) = 0.

This means

cosx = 1/2 or -1

Use that to find the three angles.

**Answer this Question**

**Related Questions**

Math - Can I please get some help on these questions: 1. How many solutions does...

Math Trig - Find all solutions on the interval [0,2pi] for the following: 2sin^2...

trig - I need to find all solutions of the given equations for the indicated ...

calculus - Find all solutions to the equation in the interval [0,2pi) Cosx-cos2x

Trigonometry - Find all solutions of the equation in the interval [0,2pi] ...

trig - Find ALL solutions to the equation on the interval [0, 2pie]: 2sin(1/2X...

Trig - Find all solutions of the equation on the interval [0,2pi): Tan^2x=1-secx

Trig - Find all solutions of equation on interval [0,2pi] 1=cot^2x + cscx

Trig - Find all of the solutions between 0 and 2pi: 2sin(x)^2 = 2 + cos(x)

identities trig? - find all solutions to the equation in the interval [0,2pie] ...