1. ## line

hey guys...i was just wondering if you could help me with these questions...
like..ok vector equation of a plane that is paralell to 3x-9y+z-12=0 and goes thru the pt 3 -7 1.

x,y,z= (3 -7 1) + s( ) + t( 3,1,0)

how...do u find s?...
and also if you had 3 pts...a, b, c...u would have to find ab..and ac...and cross product them...to find the normal rite?...then use a as ur pt...and how would u find the other directional vector for that?..

thankssss <3

2. Originally Posted by rabiatoor
hey guys...i was just wondering if you could help me with these questions...
like..ok vector equation of a line that is paralell to 3x-9y+z-12=0 and goes thru the pt 3 -7 1.

[snip]
A vector in the direction of the line is <3, -9, 1>. A point on the line is (3, -7, 1).

Therefore vector equation of line is r = (3, -7, 1) + t <3, -9, 1>

3. umm but..arent u supposed to have 2 directional vectors?...

4. Originally Posted by rabiatoor
umm but..arent u supposed to have 2 directional vectors?...
No. You're getting confused with the vector equation of a plane. Go back and read your notes.

5. oh LOLZ
thats what im looking for lolz
i typed the wrong thing
i was trying to find the vector equation of a plane please =]

6. Originally Posted by rabiatoor
oh LOLZ
thats what im looking for lolz
i typed the wrong thing
i was trying to find the vector equation of a plane please =]
Then I can't make much sense of your original post. Please post the question exactly as it's written.

7. ok that is how it is written..
i edited my original question
thanks again =]

8. Originally Posted by rabiatoor
hey guys...i was just wondering if you could help me with these questions...
like..ok vector equation of a plane that is paralell to 3x-9y+z-12=0 and goes thru the pt 3 -7 1.

x,y,z= (3 -7 1) + s( ) + t( 3,1,0)

how...do u find s?...
and also if you had 3 pts...a, b, c...u would have to find ab..and ac...and cross product them...to find the normal rite?...then use a as ur pt...and how would u find the other directional vector for that?..

thankssss <3
A normal vector to your plane is <3, -9, 1> and the plane passes through the point (3, -7, 1). Try reading this: Finding equations of planes using normal vectors