Question

(sin 26 -sin 86) /2 sin 34

Answer 1

$frac{sin26-sin86}{2sin34}= frac{2sin frac{26-86}{2}*cosfrac{26+86}{2} }{2sin34} = frac{-sin30*cos56}{sin34} =- frac{sin30*sin34}{sin34} =-1/2$