已知sin(π-α)-cos(π+α)=根号2分之4,求sin(π+α)+cos(3π-α)的值

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已知sin(π-α)-cos(π+α)=根号2分之4,求sin(π+α)+cos(3π-α)的值

已知sin(π-α)-cos(π+α)=根号2分之4,求sin(π+α)+cos(3π-α)的值
已知sin(π-α)-cos(π+α)=根号2分之4,求sin(π+α)+cos(3π-α)的值

已知sin(π-α)-cos(π+α)=根号2分之4,求sin(π+α)+cos(3π-α)的值
化简后发现右式与左式为相反数,即右式=-√2/4
sin(a+b)=sinacosb+cosasinb
sin(a-b)=sinacosb-cosasinb
cos(a+b)=cosacosb-sinasinb
cos(a-b)=cosacosb+sinasinb