若平面向量a,b满足|a+b|=1,a+b平行于x轴,b=(2,1),则a=?
人气:420 ℃ 时间:2020-01-31 23:05:23
解答
设a=(x,y)
则a+b=(x+2,y+1)
a+b平行于x轴 故y+1=0 y=-1
|a+b|=1 则x+2=1或-1
得到x=-1 或-3
a=(-1,-1)或(-3,-1)
推荐
- 若平面向量a,b,满足|a+b|=1,a+b平行于x轴,向量b=(2,-1),则向量a=
- 若平面向量a,b满足|a+b|=1,a+b平行与x轴,b(2,-1)则a=?
- 若平面向量ab满足|a+b|=1,a+b平行于x轴,b=(2,-1),则a=
- 若平面向量a,b 满足丨a+b丨=1,a+b平行于x轴,b=(2,-1),则a=
- 若平面向量a,b满足|a+b|=1,a+b平行于y轴,a=(2,-1),则b=_.
- 2-π的绝对值-根号(3-π)的平方+(π-3)的零次方=多少
- There will be no space to live_the earth in the future A.on B.in C.in on D.on in
- 解方程3y-4y=-25-20
猜你喜欢