Solving trig identities

Question

No restrictions on Θ.

 

2cosΘ-1=0

Answer 1

2cosΘ-1=0

 

2cosΘ = 1

 

cosΘ = 1/2 

 

cosΘ is positive in the first and 4th quadrant cosΘ = 1/2  at 60degrees and 300 degrees

or pi/3 rad and 5pi /3

Answer 2

cosθ=1/2, then θ=2kπ+π/6 or 2kπ-π/6 (k∈Z).

Answer 3

Hi Chloe,

 

2cosθ-1=0

2cosθ =1

cosθ =1/2

 

θ =π/3 = 60° or θ=5Π/3 =300°

 

 

 

Meena from Strongsville,OH