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Print Name:
Student Number:
Section Time:
Math 20C.
Final Exam
December 8, 2005
Read each question carefully, and answer each question completely.
Show all of your work. No credit will be given for unsupported answers.
Write your solutions clearly and legibly. No credit will be given for illegible solutions.
1. (8 Pts.) Find the equation of the plane that contains both the point (

1
,
0
,
1) and the
line
x
=
t
,
y
=

1 + 2
t
,
z
= 3
t
.
The plane is determined by a point in the plane and the normal vector. A point in the plane
is
P
0
= (

1
,
0
,
1).
To compute the normal vector
n
, notice that the equation of the line is given by
r
(
t
) =
h
0
,

1
,
0
i
+
h
1
,
2
,
3
i
t
.
Denote
v
=
h
1
,
2
,
3
i
, and
P
1
=
r
(0) = (0
,

1
,
0).
Then,
~
P
1
P
0
=
h
1
,
1
,
1
,
i
. Therefore,
n
=
v
×
~
P
1
P
0
=
¯
¯
¯
¯
¯
¯
i
j
k
1
2
3

1
1
1
¯
¯
¯
¯
¯
¯
=
h
(2

3)
,

(1 + 3)
,
(1 + 2)
i
,
n
=
h
1
,

4
,
3
i
.
Then, the equation of the plane is

(
x
+ 1)

4(
y

0) + 3(
z

1) = 0
,
⇒

x

1

4
y
+ 3
z

3 = 0
,
x
+ 4
y

3
z
=

4
.
#
Score
1
2
3
4
5
6
7
8
9
10
Σ
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View Full Document 2. (8 Pts.) Find the values of the constants
a
and
b
such that the function
f
(
t, x
) = sin(
x

at
) + cos(
bx
+
t
)
is solution of the wave equation
f
tt
= 4
f
xx
.
f
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This note was uploaded on 04/30/2008 for the course MATH 20C taught by Professor Helton during the Fall '08 term at UCSD.
 Fall '08
 Helton
 Math, Calculus

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