貌似不难,sin(a+b)cos(c-b)-cos(b+a)sin(b-c)sin(a-b)sin(b-c)-cos(a
来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/10/05 05:35:52
貌似不难,
sin(a+b)cos(c-b)-cos(b+a)sin(b-c)
sin(a-b)sin(b-c)-cos(a-b)cos(c-b)请写出详细过程.(不然本人看不懂)
为什么?我写的不够清楚还是...
sin(a+b)cos(c-b)-cos(b+a)sin(b-c)
sin(a-b)sin(b-c)-cos(a-b)cos(c-b)请写出详细过程.(不然本人看不懂)
为什么?我写的不够清楚还是...
1.sin(a+b)cos(c-b)-cos(b+a)sin(b-c)=sin(a+b)cos(c-b)+cos(a+b)sin(c-b)
=sin[(a+b)+(c-b)]=sin(a+c)
2.sin(a-b)sin(b-c)-cos(a-b)cos(c-b)=sin(a-b)sin(b-c)-cos(a-b)cos(b-c)
=-[cos(a-b)cos(b-c)-sin(a-b)sin(b-c)]=-cos[(a-b)+(b-c)]=-cos(a-c)
=cos(a-c)
参考正弦和余弦和与差的公式即可
=sin[(a+b)+(c-b)]=sin(a+c)
2.sin(a-b)sin(b-c)-cos(a-b)cos(c-b)=sin(a-b)sin(b-c)-cos(a-b)cos(b-c)
=-[cos(a-b)cos(b-c)-sin(a-b)sin(b-c)]=-cos[(a-b)+(b-c)]=-cos(a-c)
=cos(a-c)
参考正弦和余弦和与差的公式即可
貌似不难,sin(a+b)cos(c-b)-cos(b+a)sin(b-c)sin(a-b)sin(b-c)-cos(a
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