1.

If `bar(DA) =bar(a); bar(AB)=bar(b)` and `bar(CB)=kbar(a)` where `k>0` and `X,Y` are the midpoint of `DB` and `AC` respectively such that `|bar(a)|=17` and `|bar(XY)|=4`, then k=

Answer» `X=(veca+vecb)/2`
`Y=(veca+vecb+veca(1-k))/2`
`Y=veca+vecb/a-(vecaK)/2`
`|XY|=4`
`XY=veca+vecb/2-(vecaK)/2-(veca+vecb)/2`
`=veca/2-(vecak)/2`
`=veca/2(1-k)`
`|XY|=4=(|veca|(1-k))/2`
`4=(17(1-k))/2`
`1-k=8/17`
`k=9/17`.


Discussion

No Comment Found