# Equation of vector pass thru point

1. May 27, 2014

### kelvin macks

1. The problem statement, all variables and given/known data

can someone draw me a better diagram for part c and d ? i cant understand the diagram given . This is the suggested ans form my book

2. Relevant equations

3. The attempt at a solution

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2. May 27, 2014

### ehild

Here you are. A is outside both planes. P is point of the intersection line l

ehild

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3. May 27, 2014

### kelvin macks

how do u know that point a is located outside? why point a cant be on the plane?

4. May 27, 2014

### ehild

Plug in the coordinates of A into the equations of both planes. Does it fit?

ehild

5. May 27, 2014

### kelvin macks

ya , the ans is correct . why? i cant understand

6. May 27, 2014

### ehild

A: x=1, y=0, z=1. A is in the plane π1 if its coordinates fulfil the equation of the plane.

Plane π1: x-y+2z=1. Plugging in he coordinates of A: 1-0+2 =3≠1
Plane π2: 2x+y-z=0. Plugging in he coordinates of A: 2-1=1≠0

A is not point of any of the planes.

ehild