Find the solution to this equation, when π≤θ≤2π.
A) 8π/13
B) 7π/5
C) 7π/6
D) 2π/3
+23254 This is a quadratic, I would write it into this form and then use the quadratic formula:
2√3cos²θ - cosθ - 2√3 = 0
cosθ = [1 ± √( 1 - 4(2√309-2√3) ) ] / ( 4√3 )
cosθ = [ 1 ± √(1 + 48) ] / ( 4√3 )
cosθ = 8 / ( 4√3 ) = 2 / √3 ---> impossible
or cosθ = -6 / ( 4√3 ) = - √3 / 2 ---> θ = 5π/6 (too small) or θ = 7π/6
+23254 This is a quadratic, I would write it into this form and then use the quadratic formula:
2√3cos²θ - cosθ - 2√3 = 0
cosθ = [1 ± √( 1 - 4(2√309-2√3) ) ] / ( 4√3 )
cosθ = [ 1 ± √(1 + 48) ] / ( 4√3 )
cosθ = 8 / ( 4√3 ) = 2 / √3 ---> impossible
or cosθ = -6 / ( 4√3 ) = - √3 / 2 ---> θ = 5π/6 (too small) or θ = 7π/6
