Question

Prove that `1+(cos105+cos165)/(sin105+sin375)=0`?

Answer 1

`LHS=1+(cos105+cos165)/(sin105+sin375)`

`=1+(2cos135cos30)/(2sin240cos135)`

`=1+(cos30)/(sin(90*3-30))`

`=1+(cos30)/(-cos30)`

`=1-1=0=RHS`