Friday

September 19, 2014

September 19, 2014

Posted by **Sandy** on Monday, March 8, 2010 at 1:25pm.

2 cos^2 x + cos x = 1

- trig -
**Damon**, Monday, March 8, 2010 at 4:49pm2 y^2 + y = 1

y^2 + (1/2)y = 1/2

y^2 + (1/2)y + 1/16 = 8/16+1/16 = 9/16

(y+1/4)^2 = 9/16

y+1/4 = -3/4 or +3/4

y = -1 or 1/2

so

cos x = -1 or cos x = 1/2

find all those places for example cos pi = -1 and cos pi/3 or 60 degrees = 1/2 as does cos of -pi/3 which is 5pi/3

**Answer this Question**

**Related Questions**

TRIG! - Posted by hayden on Monday, February 23, 2009 at 4:05pm. sin^6 x + cos^6...

Math - Solving for Trig Equations - Solve the following equation for 0 less than...

trig - Reduce the following to the sine or cosine of one angle: (i) sin145*cos75...

Math - Solving Trig Equations - What am I doing wrong? Equation: sin2x = 2cos2x ...

Trig--check answer - Solve the equation of the interval (0, 2pi) cosx=sinx I ...

trig - how would you verify this trig identity (1+cos(x) / 1-cos(x)) - (1-cos(x...

Math - Solving Trig Equations - Solve each equation for o is less than and/or ...

Precalc with Trig - What value(s) of x from 0 to 2pi solve the following ...

trig - Show that 1-cos2A/Cos^2*A = tan^2*A 1-cos2A/Cos^2*A = [Cos^2(A) - Cos(2A...

trig - it says to verify the following identity, working only on one side: cotx+...