1.已知两点M(3,-2)和N(-5,-1),点P满足向量MP=二分之一向量MN,求点P的坐标?2.已知向量a=(3,4),b=(sinX,cosX)且向量a平行于向量b,求tanX3.已知向量e1=(-1,2)e2=(-2,3)a=(-1,2),以向量e1e2为
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![1.已知两点M(3,-2)和N(-5,-1),点P满足向量MP=二分之一向量MN,求点P的坐标?2.已知向量a=(3,4),b=(sinX,cosX)且向量a平行于向量b,求tanX3.已知向量e1=(-1,2)e2=(-2,3)a=(-1,2),以向量e1e2为](/uploads/image/z/4033678-22-8.jpg?t=1.%E5%B7%B2%E7%9F%A5%E4%B8%A4%E7%82%B9M%EF%BC%883%2C%EF%BC%8D2%EF%BC%89%E5%92%8CN%EF%BC%88%EF%BC%8D5%2C%EF%BC%8D1%EF%BC%89%2C%E7%82%B9P%E6%BB%A1%E8%B6%B3%E5%90%91%E9%87%8FMP%3D%E4%BA%8C%E5%88%86%E4%B9%8B%E4%B8%80%E5%90%91%E9%87%8FMN%2C%E6%B1%82%E7%82%B9P%E7%9A%84%E5%9D%90%E6%A0%87%3F2.%E5%B7%B2%E7%9F%A5%E5%90%91%E9%87%8Fa%3D%EF%BC%883%2C4%EF%BC%89%2Cb%3D%EF%BC%88sinX%2CcosX%EF%BC%89%E4%B8%94%E5%90%91%E9%87%8Fa%E5%B9%B3%E8%A1%8C%E4%BA%8E%E5%90%91%E9%87%8Fb%2C%E6%B1%82tanX3.%E5%B7%B2%E7%9F%A5%E5%90%91%E9%87%8Fe1%3D%EF%BC%88-1%2C2%EF%BC%89e2%3D%EF%BC%88-2%2C3%EF%BC%89a%3D%EF%BC%88-1%2C2%EF%BC%89%2C%E4%BB%A5%E5%90%91%E9%87%8Fe1e2%E4%B8%BA)
1.已知两点M(3,-2)和N(-5,-1),点P满足向量MP=二分之一向量MN,求点P的坐标?2.已知向量a=(3,4),b=(sinX,cosX)且向量a平行于向量b,求tanX3.已知向量e1=(-1,2)e2=(-2,3)a=(-1,2),以向量e1e2为
1.已知两点M(3,-2)和N(-5,-1),点P满足向量MP=二分之一向量MN,求点P的坐标?
2.已知向量a=(3,4),b=(sinX,cosX)且向量a平行于向量b,求tanX
3.已知向量e1=(-1,2)e2=(-2,3)a=(-1,2),以向量e1e2为基底,试将向量a分解为 入1向量e1+入2e2的形式
1.已知两点M(3,-2)和N(-5,-1),点P满足向量MP=二分之一向量MN,求点P的坐标?2.已知向量a=(3,4),b=(sinX,cosX)且向量a平行于向量b,求tanX3.已知向量e1=(-1,2)e2=(-2,3)a=(-1,2),以向量e1e2为
1
设P(x,y),则:MP=OP-OM=(x,y)-(3,-2)=(x-3,y+2),MN=ON-OM=(-5,-1)-(3,-2)=(-8,1)
而MP=MN/2,即:(x-3,y+2)=(-8,1)/2,故:x-3=-4,y+2=1/2,即:x=-1,y=-3/2
即点P(-1,3/2)
2
a与b平行,则存在关系:b=ka,即:(sinx,cosx)=k(3,4),即:sinx=3k,cosx=4k
即:tanx=3/4
3
k1、k2表示lambda1、lambda2,k1e1+k2e2=k1(-1,2)+k2(-2,3)=(-k1-2k2,2k1+3k2)=a=(-1,2)
即:-k1-2k2=-1-------(1)
2k1+3k2=2-------------(2)
(1)*2+(2)得:k2=0,k1=1
(-1,-2/3) 3/4 入1=1 入2=0