trig
posted by Sandy .
Solve the following for x, where 0 < x < 2 pi.
2 cos^2 x + cos x = 1

2 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
Respond to this Question
Similar Questions

trig
Show that 1cos2A/Cos^2*A = tan^2*A 1cos2A/Cos^2*A = [Cos^2(A)  Cos(2A)]/Cos^2(A). Substitute: Cos(2A) = 2Cos^2(A)  1: [1  Cos^2(A)]/Cos^2(A)= Sin^2(A)/Cos^2(A) = tan^2(A) 
trig
Reduce the following to the sine or cosine of one angle: (i) sin145*cos75  cos145*sin75 (ii) cos35*cos15  sin35*sin15 Use the formulae: sin(a+b)= sin(a) cos(b) + cos(a)sin(b) and cos(a+b)= cos(a)cos(b)  sin(a)sin)(b) (1)The quantity … 
trig
how would you verify this trig identity (1+cos(x) / 1cos(x))  (1cos(x) / 1+cos(x)) = 4cot(x)csc(x) ? 
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  Attempt: 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)= … 
Math  Solving Trig Equations
Solve each equation for o is less than and/or equal to theta is less than and/or equal to 360  sin^2x = 1 = cos^2x  Work: cos^2x  cos^2x = 0 0 = 0  Textbook Answers: 90 and 270  Btw, how would you isolate for cos^2x = 0? 
Math  Solving Trig Equations
What am I doing wrong? Equation: sin2x = 2cos2x Answers: 90 and 270 .... My Work: 2sin(x)cos(x) = 2cos(2x) sin(x) cos(x) = cos(2x) sin(x) cos(x) = 2cos^2(x)  1 cos(x) (+/)\sqrt{1  cos^2(x)} = 2cos^2(x)  1 cos^2(x)(1  cos^2(x)) 
TRIG!
Posted by hayden on Monday, February 23, 2009 at 4:05pm. sin^6 x + cos^6 x=1  (3/4)sin^2 2x work on one side only! Responses Trig please help!  Reiny, Monday, February 23, 2009 at 4:27pm LS looks like the sum of cubes sin^6 x + cos^6 … 
Precalc with Trig
What value(s) of x from 0 to 2pi solve the following equation: cos squared x  cos x  6 = 0 
Calculus
how do you solve this trig identity? i don't get it at all! cos(a+b)cos(ab)=cos^2acos^2b1 
PreCal (Trig) Help?
The following relationship is known to be true for two angles A and B: cos(A)cos(B)sin(A)sin(B)=0.957269 Express A in terms of the angle B. Work in degrees and report numeric values accurate to 2 decimal places. So I'm pretty lost …