เฉลยคณิต ครูพี่กอล์ฟ
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เฉลยคณิตครูพี่กอล์ฟ ม.ปลายTRANSCRIPT
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..
Vol.4 4 5 8
(diff L' Hospital)x 1lim
7 3x x+ 3
10 x 8x+1=
00
=x 1lim
1
2 73x(3) 1
2 x+3(1)
1
2 10x( 1) 1
2 8x+1(8)
=
32
12
13
83
=23
12k = 12 23 = 8 7 7 53
Con x = 2 f (2) function $% : f(2) = a b
x 2lim f (x) =
x 2lim x
3 3x 2x 2
=
x 2lim 3x
2 31
= 3 (4) 3 = 9
00
x 2+lim f (x) =
x 2+lim x2 + ax + 1 = 4 + 2a + 1 = 2a + 5
'() 2a + 5 = 9 a = 2
*( a b = 9 2 b = 9 b = 7
a2 + b2 = 22 + (7 )2 = 53
17 13 2
f (x) = 2x , x 02 , x < 0
f ( 5) = 2f (3) = 2(3) = 6
=
1
-
18 13 2' f (x) = d
dxf(x) =
h 0lim
f (x+ h) f (x)h
1 = d (sin x)dx h 0
limsin (x+ h) sin x
h
2 = d (x+ 1)dx h 0
lim((x+ h) + 1) (x+ 1)
h=
x0lim
((x+ x) + 1) (x+ 1)x
3 = d (e2x)
dx h 0lim e
2(x+h) e2x
h=
x 0lim e
2(x+ x) e2x
x
4 = d (2x2
1)dx h 0
lim(2 (x+ h)2 1) (2x2 1)
h
21 15 54.'/0123456278$290$2$: 4 1;( t = 0 => 2$?2%f(4) (0)
' f (t) = 4f (t) 3f (t) + 1 (1)
f (t) = 4f (t) 3f (t) (2)
f(4) (t) = 4f (t) 3f (t) (3)
f(4) (0) = 4f (0) 3f (0) (4)
*/2 t = 0 @2 (1) , f (0) = 4f (0) 3f (0) + 1 = 4(2) 3 (1) + 1 = 6
*/2 t = 0 @2 (2) , f (0) = 4f (0) 3f (0) = 4 (6) 3 (2) = 18
*/2@2 (4) , f(4) (0) = 4 (18) 3 (6) = 54 25 17 4
' xy = c y = cx y = cx1 y = cx2 = cx2
B667C'7B$6D$B> a , ca m =
yx =
2 25 1
= 1
m.>% 1;( x @G > y = c
x2
m.>% /3? > a , ca ca2
* m.>% /3? a , ca = m
c
a2= 1 c = a2 (1)
(1,2)(5,-2)
(a, )ca
y = cx
m
2
-
m ''7 $: (1 , 2)a , ca = m =
ca 2
a 1 1
= , */2 '()ca 2 a + 1 c = a2
= a2a 2 a + 1
2a = 3 a = 32
*/2@2 (1) , c = 32 2
=94
26 17 3*'7$ y = 2x2 + 8x + 6 (1)
y = 2x + 6 (2)
' (1) *( (2) , 2x2 + 8x + 6 = 2x + 6
2x2 + 10x = 0 2x(x 5) = 0 x = 0 , 5
*/2@2 (2) , 5 x = 0 ) y = 6 , 5 x = 5 ) y = 4
'7$ > (0 , 6) $: (5,4)@ y = f(x) = 2x2 + 8x + 6
f (x) = 4x + 8m1 = f (0) = 8
m2 = f (5) = 4(5) + 8 = 12
B6K : L1 y 6 = 8(x 0) y = 8x + 6 (3)
B6K : L2 y (4) = 12(x 5) y = 12x + 56 (4)
*/2 @2 (3) ) (3) (4), 0 = 20x 50 x = 52
x = 52
y = 8 52 + 6 = 26 (a , b) > 52, 26 a + b = 28.5
(a,b)
(0,6) (5,-4)
L : m = 81 1 L : m = -122 2
3
-
30 19 3 @ 8./. B63?6N2.>% = A
A = 12(20 2r)r = (10 r)r = 10r r2
dAdr
= 10 2r = 0
r = 5
= K%P2C6KAmax (10 5)(5) = 25
32 21 6' f (x) = 3 x + 5 = 3x
12 + 5
f(x) = f (x)dx = (3x12 + 5)dx = 3x
32
32
+ 5x + c = 2x x + 5x + c
.'/0: f(1) = 5 f(1) = 2 + 5 + c = 5 c = 2
f(x) = 2x x + 5x 2
x 4lim
f(x2) 2f(x) =
f(16) 2f(4) =
(32 16 + 80 2) 216+ 20 2
=20434
= 6
34 22 7'.'/0 ">6S$21%B2B$6D$B /3?'7 (2 , 19) /$: 19"*B% *( f(2) = 19f (2) = 19
f (x) = f (x)dx = (6x + 4)dx = 3x2 + 4x + c f (2) = 12 + 8 + c = 19 c = 1 f (x) = 3x2 + 4x 1
f(x) = f (x)dx = (3x2 + 4x 1)dx = x3 + 2x2 x + c f(2) = 8 + 8 2 + c = 19 c = 5 f(x) = x3 + 2x2 x + 5
f(1) = 1 + 2 1 + 5 = 7
2 39 22?%' a, b, c CK/3?B6 KUK3:/3: '(% a3, b3, c3
a3 = 1 + 3 4 3
= 1 + 3 3 4 + 3 3 16 + 4 = 5 + 3 3 4 + 3 16 b3 = 3 2 + 3 3
3= 2 + 3 3 4 3 3 + 3 3 2 3 9 + 3 = 5 + 3 3 12 + 3 18
r r
20 - 2r
4
-
8: *2G b > a $1 4 /C4%) b3 > a3
/3:$: c3 = 11 a3 = 5 + 3 3 4 + 3 16 1 G 2 G
8: a > c $1 1 *( 3 /C4%) : 1 2a3 > c3
1234@SBXK : (a + b)3 = a3 + 3a2b + 3ab2 + b3
5 41 1
= 27 y = 35x 9x2log3
log2log 5
log 4log 7
log 6
log3
log4log 5
log 6log 7
log 8
= = 35x (32)x2 33 log3log2
log5
log4log7
log6log4
log3log6
log5log8
log7
= = 35x+ 2x2 33 log8log2
=log23
log2=
3 log2
log2= 3
= 3 5x + 2x2 xy = 12 3
=18
= 02x2 + 5x 3
= 0(2x 1)(x + 3)
x = 12, 3
.'/0: x R+
7 42 1 1 ! 2Y)U132KZlogxx =
log2
2
2 log x = x log 2 log x2 = log 2x
x2 = 2x
>Y: > x = 2 , 4 2 "# 8K(6?2Y (1 , 0) *( */2@2 U[2'KC% (9,2) y = log 1
3
x
3 %&' 4 5X *2G
y
x
(4,16)
(2,4)
y = x2
y = 2 x
'723463> x U[2:)68C'K;
5
-
15 46 3log82 + log84 + log88 + log816 + ... + log82
n= 210
log232 + log2322 + log232
3 + log2324 + ... + log232
n= 210
13
+ 23
+ 33
+ 43
+ ... + n3
= 210
= 6301 + 2 + 3 + 4 + ... + n
= 630n(n+1)2
= n(n + 1) 1260 = 35 36
n = 35 16 46 1
a =n = 2
9 log 1 1n2 = n = 2
9 log n
2 1n
= n = 29 log (n 1)(n+ 1)n2
=n = 2
9 log n 1n n+ 1n
a = log 12 32 + log 23 43 + log 34 54 + ... + log 89 109 a = log 12 32 23 43 34 54 ... 89 109 = log 1018 = log 59
10a = 59
18 47 10@ '() logxy + logyx = 103 A = logxy ,
1A
= logyx
A + 1A
=103
3A2 + 3 = 10A 3A2 10A + 3 = 0 (3A 1)(A 3) = 0
A = 13, 3 logxy =
13, 3 y = x
13 , x3
() 1 , ' y = x13 xy = 16 x x
13 = 16 x
43 = 16
(x43 )
34 = (16)
34 x = (24)
34 = 23 = 8 y = x
13 = 8
13 = 2
$%2$42 x + y = 8 + 2 = 10
() 2 ' x = 2y = x3, xy = 16 x x3 = 16 x4 = 16
y = x3 = 23 = 8 x + y = 2 + 8 = 10
6
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20 48 f1(x) = 12log x1x1
y = f(x) = 10x 10x10x + 10x
=
10x 110x
10x + 110x
=
102x 1
10x
102x +110x
=102x 1
102x + 1
inverse U3?2 x U[2 y , U3?2 y U[2 x '()x = 10
2y 1
102y +1 x(102y + 1) = 102y 1 x(102y) + x 102y = 1
102y(x 1) = x 1 102y = x 1x 1
2y = log x 1x 1 y = 1
2log x 1x 1 f1(x) = 12 log x 1x 1
22 49 2logc+ ba + logc ba = x(logc+ ba)(logc ba)
log a
log (c+ b) +log a
log (c b) =x log a
log (c+ b) log a
log (c b)
2Y >X;/78'20@2B6K log (c + b) log (c b)
log (c b) + log (c + b) = x log a
*(.'/0: log(c2 b2) = log ax a2 + b2 = c2
log a2 = log ax
x = 2 25 51 > a )66
1234U[21B:.> 6.S. P\?%.'/02'(DC8K('.'/0 log a = 2 log( x 2 + x + 2 ) log x
log a = log( x 2 + x + 2 )2 log x
log a = log
( x 2 + x+ 2 )2x
a = ( x 2 + x+ 2 )2
x (1)
'%?2)1$% % > 0 *( /Y@ log 1 x 2
%*/2 x 'Y22=6/3? @2 (1) 2*/2 @S)6) a %U[2'Y22KK(x = 2 : a = (0+ 2)
2
2= 2
.... ........
7
-
*/2 x = 3 : a = (1+ 5 )2
2=
6+ 2 5
3
*/2 x = 4 : a = ( 2 + 6 )2
4=
8+ 2 12
4= 2 + 3
*/2 x = 5 : a = ( 3 + 7 )2
5=
10+ 2 21
5
8:5K*/2 x 'Y22=6)UK?G '()> a 66> 1 63 544
B66C>K:>K$/3? 1 : >K:>K$/3? 2 : A,B, a, b M,N, m, n 8, *6 X 8, *6 X
'$8, *6 /$4% 2 >K:>K$2$?%2 *2YXG 1B3:() 1 : A, B XK%16
- M, N B$:$2) 2! C93- X>K:>K$/3? 1 1B3:@2/3?% 4 S%) C934 3- X>K:>K$/3? 2 1B3:@2/3?% 4 S%) (1S%3$:>K:>K$*K))
/Y) C934 3
K;3/3? 1 /Y) C932! (4 3) (4 3) = 288
() 2 : A, B C$2
A
B
M N
LOCK
A
M
N B
LOCK1 2
34
8
-
- B XPK11% A /Y) 2 C93- B$: M, N ) 2! C93- X>K:>K$/3? 1 1B3:) 2 *:: >
S% 1, 2, 3 - >2(S% /Y) C93 S%/3?3 2
K6 8 C93- S%3$2 /Y) 2 C93
S% 2 /2$42*(B$: a, b ) 2 C93- X>K:>K$/3? 2 /Y62>K:>K$*K /Y) 8 C93
K;3/3? 2 /Y) C932 2! 8 8 = 256
K6 2 K;3) C93288 + 256 = 544 4 64 3
__ __ __ __ __ __ __
x ) 7 $' 3 9 B$: 4 $
() 1 x )6@S 0, 1, 2 /Y) C937 4! = 168
() 2 x U[2 0, 1 K 2 /Y) C933 4!2!
= 36
x ' 0, 1, 2 B$:*::63PY4 1 >X
C93/$4%6 C93= 168 + 36 = 204
7 66 3521 1 - 10 1( 4 >(*22, 1 11 - 20 1( 1 >(*22 K6 50 >(*22%K/Y) 45 >(*22 *U /YDC 5 >(*22() 1 DC1 4 >(*22 1 1, 1 1 >(*22 1 1
/Y) C93 101 101 = 100() 2 DC1 1 >(*22 5 1 /Y) C93 105 = 252 C93/$4%6 C93= 100 + 252 = 352
3 9 2
1 C93 0, 1, 2, x
9
-
14 69 7' /7 *B% *( f(x) x x A f(1) 1 f(2) 2
A B () 1 1 /&0 2 *( 2 /&0 1, 3, 41 1 1 C93 3 C93 = 3 C932 2 $@$2\?%/3? 1 )6
3 () 2 1 /&0 3, 4 *( 2 /&0 1, 3, 44 2 C93 2 C93 = 4 C93
C93/$4%6 C93= 3 + 4 = 7 16 70 0.7
n(s) = 53 = 10E : D:U[2'Y22>XKD>X;U[2'Y22>3? 63 2 K;3
K;3/3? 1 : >X, >3?, >3? 63 C93 21 32 = 6 K6 C937
K;3/3? 2 : >3?, >3?, >3? 63 C93 33 = 1 P(E) = n(E)
n(S) =710
= 0.7
17 71 1n(s) = 104 = 210E : () 1 : 63 C93+,+,+, 53 51 = 50
K6 C93100
63 C93+,,, 51 53 = 50 P(E) = n(E)
n(S) =100210
=1021
19 72 2n(s) = 72 = 21E : C:)6)B3Y *U %C:'B3*% + 1/2$42 P\?%63 5 X
n(E) = 52 = 10 P(E) = 1021
10
-
21 73 196 49pi196
n(s) = 8./. = 14 14n(s) = 8./. *K% = 14 14 pi(72)
P(E) = 196 49pi196
24 74 3n(s) = 6 6 = 36E : (1, 6) (6, 1) (2, 5) (5, 2) (4, 3) (3, 4) (6, 2) (2, 6)
P(E) = n(E)n(S) =
836
=29
29 77 0.55 P((A B) ) = 0.55
7
7
7 7
7
7
77
A B
0.15 0.15 0.15
0.55
11
-
30 77 1S : 2Y a, b, c, d, e, f 6B$:/3?)U6 C93n(s) = 6! = 720E : *U $*K)6@S a *( b *($B7/)6@SBK(A B
__ __ __ __ __ __ c, d, e, f CBK( b, c, d, f
8:$*K*($B7/ 63 c, d, f /3?@SK6$2'\%%*K;34!
() 1 /Y) C931 __ __ __ __ 4 1 4! 4 = 96 K6
4! 312 C93() 2 /Y) C933 __ __ __ __ 3 3 4! 3 = 216
P(E) = 312720
=1330
32 78 2' =Tr+ 1 nr an r br
= 10r 2x3 10 r
x3
y2
r
= 10r 210 r x30+ r (x3)r
y2r
= x
6
y12r = 6
B.U.B. 1% > x6y12
106 210 6 = 3, 360 2 93 3
u = 4a + 2b c = 4 21 + 2 32 10 = 18 >6S$21% u = mu = 8
1= 8
Vector /3?$4%j$: %63>6S$2 u = 18
'$/$4% 4 8: 6313/3? >1 3m = 18
3 94 10' a + b 2 = a 2 + 2a b + b 2
132 = 102 + 2a b + 72 a b = 10
e
c, d, f
b, c, d, f
b, c, d, f /3?)6PY4$:$*K
12
-
12 98 1' a b a b = 0 3x + 2y = 0 y = 3
2x (1)
' a = 4 x2 + y2 = 4 x2 + y2 = 16 (2)
*/2 @2 (2), y = 32x x2 + 32x
2= 16 x2 + 9
4x2 = 16 13x
2
4= 16
*/2@2 (1) 8?> y13x2 = 64 x2 = 6413
x = 813
5 x = 813
y = 32
813
= 1213
5 x = 813
y = 32
813
= 1213
*(.'/0: a c > 0 2x + 3y > 0 2x > 3y
K;3 )6'KC%x = 813
, y = 1213
2 813
> 3
1213
K;3 'KC%x = 813
, y = 1213
2 813
> 3
1213
x y = 813
12
13=
20
13
14 99 1U[2B6:$C12\?%1% vector 3 6CC
17 101 1.5@ AB = u , AD = v
AM = AB + BM = u + 13v
AN = AD + DN = v + 13u
AM + AN = u + 13v + v + 1
3u
AM + AN = 43(u + v) = 4
3(AC)
AC = 34(AM) + 3
4(AN)
'() = 34, = 3
4 + = 3
4+ 34
=32
= 1.5
A
D C
B
1
2
21
u
v
N
M
13
-
4 111 31 3 DC S2 A = {1, 2} B = {1} C = {2}
P(A) = {, {1}, {2}, {1, 2}}
P(B) = {, {1}}
P(C) = {, {2}}P(B) P(C) = {, {1}, {2}}8: P(A) P(B) P(C)
6 112 4' set B : x2 4x + 3 = 0 (x 3)(x 1) = 0 x = 3, 1
B = {3, 1} , C = {1, 2, 3, .....}
A C = {4,3,2,1, 0}
63'Y22B6SC 7 $(A C) B = {4,3,2,1, 0, 1, 3}
7 113 2'.'/0 *B%C A B
1 1 (C A) (C B) C1 2 (A C) (B C)
= (A B) C = C1 3 (A C) (B C)
= (A B) C C1 4 (A B C) (A B)
10 114 9'B6SC 1, 2, 3, ....., 10 8: P\?%K 5 %$1 + 2 + 3 + ..... + 10 = 55
$%2$42 KB6SC6 8 $ * DK6$%>%K 5 %$'\%62$:KB6SC 2 $ ' 10 $ .
D:1% 2 $2$42%K 5 %$S2$2 '() B6SC 2 $/3?) 63$%234
K6 9 C93(1, 4) (1, 9) (2, 3) (2, 8) (3, 7) (4, 6) (5, 10) (6, 9) (7, 8)
A B
C
14
-
11 115 48C'K;B6SC *($@2 8: *($'(63/%A B = {1, 2, 3, 4} A B
3 %> )UX@2P A %3, )UX@2P B %3K)UX@2P A *( B /$4%B%P (*'()6X@2 A K B )6)) '(BK%) C933 3 3 3 = 81*@2 81 C93/3?)%$ 2 C93 >
1. 1, 2, 3, 4 )UX@2 A 6 B '(U[2 2. 1, 2, 3, 4 )UX@2 B 6 A '(U[2
C93KBK% A *( B > C9381 2 = 79 14 116 26
n(UUUU) = 66 2$K32/3?B:)CS3 = 6 x + y + z = 6' n(UUUU) = 66(x + y + z) + 10 + 11 + 17 + 13 + m = 66 m = 9
'Y22>2/3?B:)CS$%mn*(>;C >2= 17 + 9 = 26
******************************
)/ $%mn
>;C
x
z
y1017
11 m
13
15