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Cozzy

Thu May 13, 2004 8:36 am


Geometery

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Hey anyone know how to do this problem

Random point = A(-2,-1,1)
Plane = 6x-7y+2z=0

a) determine a point, x, on the plane

b) determine the magnitude of the projection of A(vector X) on the normal vector to the plane.

c) explain the signifince of the magnitude

plz show answer if u can
please
thx  :D


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Dan

Thu May 13, 2004 1:55 pm



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AHHHHHHHHHHHHHHHHHHHHHHHHHH not geo math, it burns my eyes!!!!!!!

Why are you trouching us with such evil........  :wall:


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Cozzy

Thu May 13, 2004 5:37 pm


come on help me

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come on dan, if u dont help me ill get tony to ban u from this site ;)

lol or else ill just go over 2 his house and play midnight club more

BUT SOMEONE HELP ME PLEASE


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Dauntless

Thu May 13, 2004 8:13 pm



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Dan can't get banned...he's the CRAZY ADMIN.......  Crazy, you hear me?


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Delos

Thu May 13, 2004 8:49 pm


Re: Geometery

-----------------------------------

Hey anyone know how to do this problem

Random point = A(-2,-1,1)
Plane = 6x-7y+2z=0

a) determine a point, x, on the plane

b) determine the magnitude of the projection of A(vector X) on the normal vector to the plane.

c) explain the signifince of the magnitude

plz show answer if u can
please
thx  :D

a)
Determine a couple of points on the plane.
eg. the x/y/z intercepts (by setting others to 0).
Then, figure out 2 direction vectors.
Convert the eqn into Vector form.
Bu now you already have a bunch of points.
But the vector eqn is a beut for the rest of the problems.

b)
Just do the usual projection thing w/ dot products.

c)
Magnitude...what do you think it is  :wink: !


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octopi

Thu May 13, 2004 9:01 pm


Re: Geometery

-----------------------------------

Hey anyone know how to do this problem

Random point = A(-2,-1,1)
Plane = 6x-7y+2z=0

a) determine a point, x, on the plane

b) determine the magnitude of the projection of A(vector X) on the normal vector to the plane.

c) explain the signifince of the magnitude

plz show answer if u can
please
thx  :D

Okay, well....Part A you just need to find a few numbers that satisfy the equations.
6x-7y+2z = 0

So, you just pick random values to x, and y, and then calculate z
6(1)-7(2)+2(4) = 0
ptX=(1,2,4)

the normal to the plane is (6, -7, 2) isn't it?
Is part b asking us to make a vector XA? using two points?
ptX(1,2,4) - ptA(-2,-1,1)
vctXA(3,3,3)

now project vctXA onto the normal:
=dot(vctXA,NORMAL)/MAG(NORMAL)
=3/sqrt(89)

or, I messed up, and its
3/sqrt(27)

I dunno, I suck at this class.


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Dan

Thu May 13, 2004 9:01 pm


Re: come on help me

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come on dan, if u dont help me ill get tony to ban u from this site ;)

lol or else ill just go over 2 his house and play midnight club more

BUT SOMEONE HELP ME PLEASE

turst me you dont whont me helping you with geo math, that class is the worst i have ever done in a subject in high school.