ΔABC中,∠60°,且CA=2,CB=1,点M满足向量BM=2AM,则向量CM*CA=
来源:学生作业帮 编辑:神马作文网作业帮 分类:数学作业 时间:2024/09/20 15:26:53
ΔABC中,∠60°,且CA=2,CB=1,点M满足向量BM=2AM,则向量CM*CA=
∠60°,那一角?
BM=2AM
BA+AM=2AM
BA=AM
c^2 = a^2+b^2-2abcosC
= 1+4-2(1)(2)cos60°
= 3
c =√3
by sine rule
a/sinA = c/sinC
1/sinA = √3/sin60°
sinA = 1/2
A = 30°
cosA = √3/2
CM.CA
= (CA+AM).CA
=(CA+BA).CA
=|CA|^2 + |BA||CA|cosA
= b^2+bccosA
=4+2(√3)(√3/2)
=4+3
=7
BM=2AM
BA+AM=2AM
BA=AM
c^2 = a^2+b^2-2abcosC
= 1+4-2(1)(2)cos60°
= 3
c =√3
by sine rule
a/sinA = c/sinC
1/sinA = √3/sin60°
sinA = 1/2
A = 30°
cosA = √3/2
CM.CA
= (CA+AM).CA
=(CA+BA).CA
=|CA|^2 + |BA||CA|cosA
= b^2+bccosA
=4+2(√3)(√3/2)
=4+3
=7
ΔABC中,∠60°,且CA=2,CB=1,点M满足向量BM=2AM,则向量CM*CA=
△ABC中,∠C=90°,且CA=CB=3,点M满足向量BM=2向量AM则CM×CA=
在△ABC中,∠C等于90°,且CA=CB=3,点M满足向量BM=2向量AM,则CM向量*CA向量=?
三角形ABC中 角C等于90度 且CA=CB=3 点M满足向量BM=2向量AM 求向量CM*向量
ABC中 C=90 CA=CB=3 点M满足向量BM=2向量MA,则向量CM点乘向量CB等于
在三角形ABC中,C=90度,且|CA|=|CB|=3 点M,N满足向量AM=向量MN=向量NB,则向量CM乘向量CN为
在三角形ABC中,点D是AB的中点,且满足|向量CD|=1/2|向量AB|,则向量CA·CB=?
三角形ABC中,ABC的对边是abc,且向量CA 点乘1/2(向量CA+向量CB)=0
若等边三角形的边长为2根号3,平面内一点M满足向量CM=1/6向量CB+2/3向量CA,则向量M
在△ABC中,∠C=45°,CA=1,CB=2,则向量CA·向量CB=
在三角形ABC中,D是AB边上一点,且向量AD=2向量DB,向量CD=1/3向量CA+n向量CB,则n
若等边三角形ABC的边长为2√3,平面内一点M满足向量CM=1/6向量CB+2/3向量CA,则向量MA*向量MB=?