Question

sin 85° – cos 65° = cos 55° Prove it Please​

Answer 1

LHS=

sin(85*)-cos(65*)=

sin(85*)-sin(90*-65*)=

sin(85*)-sin25*=

2cos(110*/2)sin(60*/2)=

2cos(55*)sin(30*)=

2cos(55*)/2=

cos(55*)=

RHS