1. ln9 (= 2ln3) 17 2.math.inha.ac.kr/~lecture/calculus/jokbo/15-2_ilsu_fin_sol.pdf · 13. C Xϯî...
Transcript of 1. ln9 (= 2ln3) 17 2.math.inha.ac.kr/~lecture/calculus/jokbo/15-2_ilsu_fin_sol.pdf · 13. C Xϯî...
1. ln 9 (= 2 ln 3)
2.
17
4
3.
⇡
6
⇣27� 5
p5
⌘
4.
4
5
5.
64
9
⇡
6. < 4, 6, 8 >
7. 20
8. 10
9. 4 sin 2 + 21
10. �2
11. ¡På\| t©Xt Ä<î
V =
Z 1
0
Z 1+p1�x
2
1
Zy/(x2+y
2)
0
dzdydx
⇣î, V =
Z 2
1
Z p1�(y�1)2
0
Zy/(x2+y
2)
0
dzdxdy, ....
!<\ \⌅⌧‰.
¯¨‡, y = 1D ¸tå\\ \⌅Xt r = 1/ sin ✓ t‡,
x
2+ y
2 � 2y = 0@ r = 2 sin ✓ t¿\,
¸tå\| t©XÏ Ä<| ƒ∞Xî º⌘�Ñ@
V =
Z⇡/2
⇡/4
Z 2 sin ✓
1/ sin ✓
Z sin ✓/r
0
rdzdrd✓
<\ \⌅⌧‰.
¸tå\| \⌅⌧ ›D t©XÏ Ä<| lXt,
V =
Z⇡/2
⇡/4
Z 2 sin ✓
1/ sin ✓
sin ✓ drd✓ =
Z⇡/2
⇡/4
(2 sin
2✓ � 1) d✓
=
Z⇡/2
⇡/4
� cos 2✓ d✓ =
�1
2
sin 2✓
�⇡/2
⇡/4
=
1
2
t‰.
12. å⌅ ·tD ‰⌧¿⇠\ \⌅Xt,
r (u, v) =< sin u cos v, u, sin u sin v >
⇣0 u ⇡
2
, 0 v 2⇡
⌘
t‡,
r
u
= < cos u cos v, 1, cos u sin v >
r
v
= < � sin u sin v, 0, sin u cos v >
r
u
⇥ r
v
= < sin u cos v, � cos u sin u, sin u sin v >
| ru
⇥ r
v
| =
psin
2u cos
2v + cos
2u sin
2u+ sin
2u sin
2v = sin u
p1 + cos
2u
t‰. 0|⌧ ·t�ÑD ƒ∞Xt,
ZZ
E
p1� x
2 � z
2dS
=
Z 2⇡
0
Z⇡/2
0
p1� sin
2u cos
2v � sin
2u sin
2v sin u
p1 + cos
2u dudv
=
Z 2⇡
0
Z⇡/2
0
cos u sin u
p1 + cos
2u dudv
=
Z 2⇡
0
�1
3
(1 + cos
2u)
3/2
�u=⇡/2
u=0
dv
= �2⇡
3
⇣1� 2
p2
⌘
=
2⇡
3
⇣2
p2� 1
⌘
t‰.
13. C� XÏ¯î ¥Ä�Ì– ⌘Ït –⇣– à‡ ⌅–⌧ ¸ L ⇠‹ƒ )•tp ⇠¿Ñ
t ë@ –D ˜
C|‡ Xê. t –X ⇠¿ÑD a| Xt,
˜
CX ‰⌧ ¿⇠›@
˜
C(t) = (a cos t, a sin t) (0 t 2⇡)
<\ \⌅` ⇠ à‰.
P =
x
3+ xy
2 � 3y
x
2+ y
2, Q =
y
3+ x
2y + 3x
x
2+ y
2|‡ X‡, · C @ ˜
C\ Xϸ �ÌD D
|‡ Xt, Green �¨– XXÏ
I
C[�C̃
Pdx+Qdy =
ZZ
D
@Q
@x
� @P
@y
dxdy
t‰. 0|⌧
I
C
Pdx+Qdy =
I
C̃
Pdx+Qdy +
ZZ
D
✓@Q
@x
� @P
@y
◆dxdy
t‰. Ï0⌧,
@Q
@x
=
@
@x
✓y
3+ x
2y + 3x
x
2+ y
2
◆=
@
@x
✓y +
3x
x
2+ y
2
◆=
�3x
2+ 3y
2
(x
2+ y
2)
2
@P
@y
=
@
@y
✓x
3+ xy
2 � 3y
x
2+ y
2
◆=
@
@y
✓x� 3y
x
2+ y
2
◆=
�3x
2+ 3y
2
(x
2+ y
2)
2
t¿\,
ZZ
D
✓@Q
@x
� @P
@y
◆dxdy = 0 t‡,
I
C̃
Pdx+Qdy =
Z 2⇡
0
✓a cos t� 3a sin t
a
2
◆(�a sin t) +
✓a sin t+
3a cos t
a
2
◆(a cos t)dt
=
Z 2⇡
0
3(sin
2t+ cos
2t)dt = 6⇡
t‰. 0|⌧,
I
C
Pdx+Qdy = 6⇡
t‰.
14. yz-…t–⌧ y
2+ z
2 4 (z � 0)x �ÌD D|‡ Xê.
r · F = 3xt¿\ ⌧∞�¨| t©XÏ ·t�ÑD ƒ∞Xt,
ZZ
S
F · ndS =
ZZZ
E
r · F dV
=
ZZ
D
Z 4
y
2+z
2
3x dxdydz
=
ZZ
D
3
2
⇥16� (y
2+ z
2)
2⇤dydz
=
Z⇡
0
Z 2
0
3
2
�16� r
4�r drd✓
=
3⇡
2
8r
2 � 1
6
r
6
�2
0
= 32⇡
t‰.
15. 8 ⇣ (1, 0, 0), (0, 1, 0), (0, 0, 1)D ¿òî …tX )�›@ x+ y + z = 1t‰.
…tD ‰⌧ ¿⇠\ \⌅Xt,
r (x, y) =< x, y, 1� x� y > (0 x 1, 0 y 1� x)
t‰. t L, 0 x 1, 0 y 1� xx �ÌD D|‡ Xê. r
x
⇥ r
y
=< 1, 1, 1 >
t¿\ x+ y + z = 1– ⇠¡t‡ ⌅ΩD •Xî Ë⌅ ï °0| nt|‡ Xt,
n =
1p3
< 1, 1, 1 > t‡,
| rx
⇥ r
y
| =p3t‰.
⌧∞�¨– XXÏ,
Z
C
F · Tds =
ZZ
S
r⇥ F · ndS
=
Z 1
0
Z 1�x
0
(�x) dydx
=
Z 1
0
x
2 � x dx
=
1
3
x
3 � 1
2
x
2
�1
0
= �1
6
t‰.