Question

Find the values of which satisfy the equation. 2 cos (2B+30°) = -√3 in the domain OP ≤B≤360°​

Answer 1

60 and 90

Explanation:

`2 \cos(2 \beta + 30) = - √(3)`

`\cos(2 \beta + 30) = - ( √(3) )/(2)`

`2 \beta + 30 = \cos {}^( - 1) ( ( - √(3) )/(2) )`

First solution.

`2 \beta + 30 = 150`

`2 \beta = 120`

`\beta = 60`

Second solution

`2 \beta + 30 = 210`

`2 \beta = 180`

`\beta = 90`