14．（2023春•宿迁期中）cos(70∘+α)sin(170∘−α)−sin(70∘+α)cos(10∘+α)\cos (70\circ +\alpha )\sin (170\circ -\alpha )-\sin (70\circ +\alpha )\cos (10\circ +\alpha )cos(70∘+α)sin(170∘−α)−sin(70∘+α)cos(10∘+α)等于((( )))