11. (2023春•辽宁月考)cos54∘cos24∘+2sin12∘cos12∘sin126∘=(\cos 54\circ \cos 24\circ +2\sin 12\circ \cos 12\circ \sin 126\circ =(cos54∘cos24∘+2sin12∘cos12∘sin126∘=( )))