HW 4, Due on Oct. 20

MATH 2050
Assignment 4
Fall 2014
Due: Monday, Oct. 20
[5]
[10]
 
 
−4
1
1. Let ~u =  2  and ~v = −3. Find the projection of ~u onto ~v ; and the projection of
3
4
~v onto ~u respectively.
2. (a) Find two orthogonal vectors in the plane x + 3y − 2z = 0.
 
3

(b) Find the projection of ~u = −1 onto the plane x + 3y − 2z = 0.
1
[5]
  

x
−4 + t
3. Calculate the distance from point P (1, 1, 1) to the line y  =  2 − t .
z
3 + 2t
[5]
4. Calculate the distance from point P (1, 1, 1) to the plane 5x − y + 2z = 1.

[5]
[10]

 
 
 
2
1
0
−1
5. Are vectors ~u = −1, ~v = 1, w
~ = 2, and ~x =  2  linearly independent?
1
2
1
1
 
 
 
1
1
0





6. Let ~u = 1 , ~v = 0 and w
~ = 1.
0
1
1
(a) Show that ~u , ~v and w
~ are linearly independent.
(b) Show that any 3-dimensional vector can be written as a linear combination of ~u,
~v and w.
~
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 
 
 
−2
1
−1
7. Let ~u =  1 , ~v = −2, and w
~ = −1.
2
−1
1
(a) Are ~u , ~v and w
~ linearly independent.
(b) Can any 3-dimensional vector be written as a linear combination of ~u, ~v and w?
~
If yes, please show your reason; if no, please provide one example.
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