Question

if cosx=-1/2 & x lies in 3rd quadrant find sin x/2.cos x/2​

Answer 1

Answer:

Explanation:

π<x<23π​⇒2π​<2x​<43π​ and sin is positive in 2nd quadrant. ∴sin2x​=5 ​2 ​​. Using 1+cosx=2cos22x​⇒cos2x​=±21+cosx​ ​.

∴tan  

2

x

​  

=−  

2

​