sin²(π+α)-cos(π+α)cos(-α)+1的值为
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/07 16:23:41
![sin²(π+α)-cos(π+α)cos(-α)+1的值为](/uploads/image/z/1105176-48-6.jpg?t=sin%26%23178%3B%EF%BC%88%CF%80%2B%CE%B1%EF%BC%89-cos%EF%BC%88%CF%80%2B%CE%B1%EF%BC%89cos%EF%BC%88-%CE%B1%EF%BC%89%2B1%E7%9A%84%E5%80%BC%E4%B8%BA)
xSJ@~P.!*(4[E=
*xRTw(mO}gv7;߷ďآ{uxӸrM*&oy{Qo?gɈS5/(-KFLO@z mR dV).EOlJx( PIv<ƙőQeՖ\stx-CF)`A}T S/9o6zM[Ljqe@U`8 O@yZ ~ʹMPZ[zlzl +@77m%˨8J+2!S{j>p+s3⟌
sin²(π+α)-cos(π+α)cos(-α)+1的值为
sin²(π+α)-cos(π+α)cos(-α)+1的值为
sin²(π+α)-cos(π+α)cos(-α)+1的值为
原式=1/2*{1-cos[2*(π+α)]}-(-cosα)cosα+1
=1/2-1/2*cos(2π+2α)+cos^2 α+1
=3/2-1/2*cos2α+(1+cos2α)/2
=3/2-1/2*cos2α+1/2+1/2*cos2α
=4/2=2
原式等于 sinα^2+cosα^2+1=1+1=2 sin²(π+α)=sin(π+a)sin(π+a)=sinα^2 可以追问望采纳
解 (sin(π+a))^2=(-sina)^2=(sina)^2
-cos(π+a)=-(-cosa)=cosa
cos(-a)=cosa
原式=(sina)^2+(cosx)^2+1=2
∵sin(π+a)=-sina
cos(π+a)=-cosa
cos(-a)=cosa
∴
sin²a-(-cosa*cosa)+1
=sin²a+cos²a+1
=1+1=2