Simplify exactly:

 sin⁡(312∘)cos⁡(87∘)−cos⁡(312∘)sin⁡(87∘)=sin⁡(\displaystyle {\sin{{\left({312}^{\circ}\right)}}}{\cos{{\left({87}^{\circ}\right)}}}-{\cos{{\left({312}^{\circ}\right)}}}{\sin{{\left({87}^{\circ}\right)}}}={\sin{{(}}})=\displaystyle {)}=  

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