sin(a)=5/13.a+b=45度,求sin(b).如题.
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sin(a)=5/13.a+b=45度,求sin(b).如题.sin(a)=5/13.a+b=45度,求sin(b).如题.sin(a)=5/13.a+b=45度,求sin(b).如题.sin(a)=
sin(a)=5/13.a+b=45度,求sin(b).如题.
sin(a)=5/13.a+b=45度,求sin(b).
如题.
sin(a)=5/13.a+b=45度,求sin(b).如题.
sin(a)=5/13→cos(a)=12/13
sin(a+b)=sin45°=√2/2
=sin(a)cos(b)+cos(a)sin(b)
=5/13·cos(b)+12/13·sin(b)
cos(a+b)=cos45°=√2/2
=cos(a)cos(b)-sin(a)sin(b)
=12/13·cos(b)-5/13·sin(b)
两式相等简化后为：
17sin(b)=7cos(b) ……①
另：sin(b)^2+cos(b)^2=1 ……②
联合①、②解出：
sin（b）=7/√338
sin(a)=5/13.a+b=45度,求sin(b).如题.
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sin(a+b)sin(a-b)=sin2a-sin2b求证
求证：sin(A+B)sin(A-B)=sinAsinA-sinBsinB
sin（a-b）=sin（a+b）吗?
SIN(B-A)=-SIN(A-B)为啥
求 sin(a+b)=?
sin（a-b）=?
【证明】Sin A+sin B=2Sin 22
证明sina sin(a+2b) - sinb sin(b+2a) =sin(a+b)sin(a-b)
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sin(a+b)cosa-cos(a+b)sina=5/13 则sin（π-B)=?
sin(45度+a)=