Ответы и объяснения

2014-02-25T14:14:54+04:00
2014-02-25T14:15:08+04:00
cos(α+β) – cos(α-β)=cos(α)cos(β)-sin(α)sin(β)-(cos(α)cos(β)+sin(α)sin(β))=-2sin(α)sin(β)=(-2)*0.625*0.8=-1