Hmm. I've never done a problem like this before. If I had to guess, I'd say that the equation you're looking for looks like 2x - 4y + 2z = A, where A is some number not equal to 9.
I suppose It would be helpful to find an equation with x and y, then another with y and z, and a third with x and z.
Let t=0
x=-1 , y=5 , and z=2.
let t=1
x=2 , y=7 , and z=1
The x,y relationship contains points (-1 , 5) and (2 , 7)
The y,z relationship contains points (5 , 2) and (7 , 1)
The x,z relationship contains points (-1 , 2) and (2 , 1)
The three equations, out of order, are
1.) y = 2/3*x + 17/3
3y = 2x +17
2x - 3y = -17
2.) z = -1/3*x + 5/3
3z = -x +5
x + 3z = 5
3.) z = -1/2*y + 9/2
2z = -y +9
y + 2z = 9
And from these three equations you can create a system to solve for the values of x, y, and z. The solution is...shoot. This system has an infinite number of solutions. Of course it does. Ah, well. I tried. Had the system had a solution, it would have been a simple enough matter of plugging the values for x, y, and z into the equation in the first paragraph, to find the value for A.
Sorry I couldn't help. Maybe you can see where I went wrong? Good luck.
2007-10-13 09:17:50
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answer #1
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answered by Mehoo 3
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Find an equation for the plane that contains the line with parametric equations
x = −1 + 3t
y = 5 + 2t
z = 2 − t
and is parallel to the plane 2x − 4y + 2z = 9.
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First check to see if the directional vector v, of the line lies in the plane.
v = <3, 2, -1>
The directional vector of the line should sum to zero in the plane if it lies in it.
2*3 − 4*2 + 2*(-1) = 6 - 8 - 2 = -4 ≠ 0
So the line cannot be in any plane parallel to the given plane.
Perhaps you meant for the parametric equation for z to be:
z = 2 + t
In that case the vector lies in the plane and we can proceed.
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If the plane is parallel to the given plane, the x, y, and z coefficients will be the same. Only the constant will be different. Since the desired plane contains the given line, pick a point on the line and plug the point into the equation of the plane to find the constant. Select t = 0 which gives the point P(-1, 5, 2).
2x − 4y + 2z = 2*(-1) - 4*5 + 2*2 = -2 - 20 + 4 = -18
The equation of the desired plane is:
2x − 4y + 2z = -18
Divide by 2 to simplify.
x - 2y + z = -9
2007-10-13 11:56:33
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answer #2
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answered by Northstar 7
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