MATHS P3 HELP!

[WellWIshER]

HOW solve 2 linear equations with 3 unknowns?

eg: 2x-2y-z=2
x-3y+z=5

 

[MAVtKnmJ]

If this is a Vector question then you have to use the Elimination Method. Kindly post the complete question for better help.

 

[MAVtKnmJ]

1 vector q:
find the equation of the plane which passes through the point (1,2,3,) and contains the line of intersection of the planes
2x-y+z=4 and x+y+z=4?

Let me know if this is correct so that I will solve the rest of the question.

Direction Ratios of the line formed due to the intersection of the two planes:

2:1:3

Fixed point of this line:

0i , 0j , -4k

Let me know.

 

[WellWIshER]

the equations given
are the equations of the planes

how to find da line of intersection of da planes?

 

[MAVtKnmJ]

Use the Elimination Method similar to the one we used in O Level Quadratics questions.

For instance here are the two equations:

2x-2y-z=2
x-3y+z=5

Start by eliminating Z which as you can see can be eliminated without multiplying the equations with anything. Then eliminate Y by multiplying equation 1 with -3 and equation 2 with 2.

I hope you can take it from here.

 

[WellWIshER]

will u take the pain of slving da whole problem?

i tried but without success

 

[MAVtKnmJ]

Well what is the answer, write it so I can tally.

 

[WellWIshER]

r=7/3i+8/3k + T(5/3i+j+4/3k)

 

[MAVtKnmJ]

Whats the question my friend.

 

[WellWIshER]

the equations given
are the equations of the planes

how to find da line of intersection of da planes?

 

[ahmed t]

u must only get the same direction vector.
the fixed point in the equation can be a lot of things.
i have a very easy way.if u have the cambridge book it should show u how to find a common perpendicular.
use the equatin of the normal for each plane and find their common perpendicular
wich is the direction vector of the line of intersection.
and by mavtknmjs process u can find the fixed point.
u must read the cambridge book first.

 

[WellWIshER]

yes i know the da common perp. method. but i dont want to rely on tht.

but i dont know how to find da fix point then

 

[ahmed t]

i know another way but is realy long, there are a lot of other ways but i dont know them
as for the fixed point ill give a simple way.
put z as 0 in both equations, or x or y anyone (just make one variable zero)
now u have 2 equations from 2 variables.solve simultaneously and get x and y
say x was 1 and y was 2 then the point would be
(1, 2, 0) as we made z=0
and why not rely on the common per
its easy and makes sense and easy to imagine

 

[WellWIshER]

guys!!


v.i.p and mind-tripping-blasting-boggling question!!!!!!!


what if i have a normal vector of da plane and a line on da plane and i want to find da other line??????

 

[ahmed t]

well it would me much better if u could give the whole question quoted from wer u got it.
cause that clearly makes no sense."find da other line" WTF does that mean
just sayin

 

[WellWIshER]

i mean tht if we have da 2 direction vectors we can find da common perpendicular! right!!!

so wat if we have 1 direction vector and a common perpendicular and we have to find da other direction vector!

 

[ahmed t]

i dunno ive done all da past papers nothin like that

 

[WellWIshER]

guys how to find da cartesian equation 4 dis:

x=(2-3t)/(1+t) y=(3+2t)/(1+t)

 

[WellWIshER]

ANYONE!!!!!!!!!

 

[ahmed t]

were do u get it from