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

1 Answer
May 14, 2018

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

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

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

=1+(cos30)/(-cos30)

=1-1=0=RHS