SOLUTION: Solve the equation cos2theta=-√3/2 A) On the Interval [0,2pi) B) On (-infinity,Infinity)

Algebra.Com
Question 810319: Solve the equation cos2theta=-√3/2
A) On the Interval [0,2pi)
B) On (-infinity,Infinity)

Answer by lwsshak3(11628)   (Show Source): You can put this solution on YOUR website!
Solve the equation cos2theta=-√3/2
A) On the Interval [0,2pi)
B) On (-infinity,Infinity)
***
cos(2x)=1-2sin^2x=-√3/2
2sin^2x=1+√3/2=(2+√3)/2
sin^2x=(2+√3)/4
sinx=±√(2+√3)/4=±√(2+√3)/2=±0.9659
A)[0,2pi)
x=1.3089,1.8327,4.4504,4.9743
..
B)(-∞,∞)
1.3089±2πk,1.8327±2πk,4.4504±2πk,4.9743±2πk, k=any integer

RELATED QUESTIONS

Solve the inequality (21/15-3x)<0, and express the solution as an interval. a.... (answered by venugopalramana)
Solve the absolute value inequality. Other than Ø, use interval notation to express the... (answered by edjones)
In 18x^3 + 24x^2 + 8x >= 0 (solved in interval notation), why is [-2/3] on it's own with... (answered by MathLover1)
The function y=ln(x+10)-2 a. has domain (-infinity, infinity) and range (-infinity,... (answered by lwsshak3)
Find the domain of f(x)=7+(sqrt3x+21), and express it using interval notation.... (answered by Nate)
I'm having some trouble with this problem: Solve the inequality x^2 less than or equal (answered by Theo)
Solve the inequality 21/15-3x<0 and express the solution as an interval. Possible... (answered by NagaDevi)
I am working on solving inequalities and then writing them in interval notation. I am... (answered by rothauserc)
For {{{f(x) = 2/(x-3)}}} , solve for the domain and range in interval notation I found (answered by josgarithmetic)