At what point the straight that passes by A(2,3,4) and B(1,0,-2) intercepts the xy plane?

Answer:

$\displaystyle (\frac{4}{3},1,0)$

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- Jun 29th 2008, 07:23 AMApprentice123straight
At what point the straight that passes by A(2,3,4) and B(1,0,-2) intercepts the xy plane?

Answer:

$\displaystyle (\frac{4}{3},1,0)$ - Jun 29th 2008, 07:33 AMgalactus
The parametric line equations are:

$\displaystyle x=1+t, \;\ y=3t, \;\ z=-2+6t$

In order to intersect the xy plane, then z must = 0.

So, from z:

$\displaystyle -2+6t=0, \;\ t=1/3$

Insert this into x and y and we get:

$\displaystyle x=4/3, \;\ y=1, \;\ z=0$