5 ú¨?
??ú¨±s
? p/
f
?¥ú¨?
?
ò yx x x=+ ?+
32
21, p ′′′y ó yx x=
4
ln p ′′y
?
y
x
x
=
+
2
1
p ′′y
?
y
x
x
=
ln
2
p ′′y
? y= sin
3
xp a′′y ′′′y × yx x=
3
cos p a ′′y ′′′y
? yx
x
=
23
e p ′′′y ù yx
x
=
?
earcsin
2
′′yp
ú yx x=
3
2cos p y
()80
? yx x= +()s21
2
hp . y
()99
3
1 ,46'',143'
2
+=?+= xyxxy 6''' =y b
2 b
33
ln4' xxxy +=
22222
7ln1234ln12" xxxxxxxy +=++=
3
2
2
3
2
1
21
43
21
'
1
2(1 )
xxx
x x
x
y
x
x
+?
+
+
==
+
+
31
2
22
2
53
2
3
(4 6 )(1 ) (4 3 )(1 )
38
2
"
2(1 )
4(1 )
xx xx x
xx
y
x
x
++?+ +
8+ +
+
+
b
4
3
321
ln21
ln2'
x
x
xxxxy
?
=???=
???
4
431
5ln6
)ln21(32"
x
x
xxxxy
?
=???=
???
b
5
3223
cos3)3(cos' xxxxy =?=
3432323
sin9cos6)3)(sin(3cos6" xxxxxxxxxy ?=?+=
3323343
''' 6cos 6 sin (3 ) 36 sin 9 cos (3 )yxxxxxxxx=? ?? ? ?
2
x
3
33 6
54 sin (27 6)cosx xx=? ? ? x b
6 xxxx
x
xxxxy sin
2
1
cos3)
2
1
)(sin(cos3'
2
5
232
?=?+=
83
35
2
22
15 1 1
" 6 cos 3 ( sin ) sin (cos )
42
yx xx x x xx x
x x
=+? ? ?
3
2
2
11
(6 )cos sin
44
x xxx=? ? x
13
2
22
133 1 1
''' (6 )cos (6 )( sin ) sin cos
24 84
22
xx
yxxxxxxx
x x
=? + ? ? ? ?
31
22
15 1 57
(6 )cos ( )sin
888
x xx x=? + ? x b
7
xxx
exxxexxey
32323
)32()'3(2' +=+=
xxx
exxxexxexy
32323
)2129()'3()32()62('' ++=+++=
xxx
exxxexxexy
32323
)185427()'3()2129()1218(''' ++=++++= b
8
222
)
1
1
arcsin2()'(arcsinarcsin)'('
2
2 xxx
e
x
xxxexexy
???
?
+?=+?=
;
)1(
)34(
arcsin)12(2
)1(
)2(
)
2
1
(
1
2
arcsin2)
1
1
arcsin2)(2(
)'
1
1
arcsin2()
1
1
arcsin2()'("
2
22
22
2
3
2
2
2
2
3
2
22
22
2
x
xx
xx
e
x
xx
xx
e
x
x
x
x
xe
x
xxx
e
x
xxe
x
xxxy
?
??
??
?
?
?
?
?
?
?
?
?
?
?
?
+?=
?
?
?
?
?
?
?
?
?
?
?
?
?+
?
??+
?
+??=
?
+?+
?
+??=
9
(80) 3 (80) 1 2 (79) 2 (78) 3 (77)
80 80 80
cos 2 3 cos 2 6 cos 2 6cos 2y x xC x xC x xC x=+ + +
80 3 79 2 78 77
2 cos 2 80 2 3 sin 2 3160 2 6 cos 2 82160 2 6sin 2x xxx xx=+? ?? ??x
80 2 2
2 ( 4740)cos 2 (120 61620)sin 2x xxx??=? +?
??
x
x
b
10
(99) 2 (99) 1 (98) 2 (97)
99 99
(2 1)sh 4 sh 4shyx xCxxC=+ + +
2
(2 1)ch 99 4 sh 4851 4ch x xxx=+ +? +?x
2
(2 19405)ch 396 shx xx=+ + x b
? p/
f
?¥ ¨?
? n
()n
y
84
ò yx= sin
2
ω ó yx
x
= 2ln
?
y
x
x
=
e
?
y
x x
=
?+
1
56
2
? ye x
x
=
α
βcos × yxx= +sin cos
44
.
3
1 )
2
2cos(2)2cos1(
2
1
1)()(
πωωω +?=?=
?
n
xxy
nnnn
1
1
2sin(2
2
nn
n
x )ω ωπ
?
?
=+ b
2
() ( ) ()
0
(2 ) (ln )
n
nkxnkk
x
n
k
yC
?
=
=
∑
(1)
1
1
ln 2 2 ln 2 ln 2
k
n
nx kxk
n
k
xC
x
?
?
=
??
=? + ?
??
??
∑
1
1
(1) ( 1)!
2 ln 2 ln ln 2
kn
xn knk
n
k
k
k
xC
x
?
?
=
????
=?+ ?
??
??
∑
b
3
∑∑
=
+
=
?
?
=
?
?
?
?
?
?
=
n
k
k
k
xk
n
n
k
k
knxk
n
n
x
k
eC
x
eCy
0
1
0
)(
)()(
!)1(1
)(
1
0
!)1(
+
=
?
=
∑
k
kn
k
k
n
x
x
k
Ce b
4??
2
1
3
1
?
?
?
=
xx
y
() ()
()
11
32
nn
n
y
xx
????
=?
????
??
????
11
11
(1) !
(3) (2)
n
nn
n
xx
++
? ?
=? ?
? ?
??
? ?
0
11 1
0
(2)(3)
1
(1) ! (1) !
(3)(2) (2) (3)
n
knk
n
k
nn nk
k
xx
xx x x
?
=
++ ?+
=
??
=? =?
?? ? ?
∑
∑
1k+
b
5 []
)(
0
)()(
)cos()(
k
n
k
knxk
n
n
xeCy β
α
∑
=
?
=
0
cos( )
2
n
xknkk
n
k
k
eC x
α
π
αβ β
?
=
=+
∑
b
6 xxxxy
22222
cossin2)cos(sin ?+=
2
1
1sin
2
x=?
13
1(1cos4)
44
cos4x
x=? ? = +
?[
() 1
4 cos(4 )
2
nn
n
yx
π
?
=+ b
à ù?f
?
?
?
?
?
?
<?
≥
=
0,
,0,
)(
2
2
xx
xx
xf
85
¥ò¨?
? b
3 ?
H ?0>x xxf 2)(' = 0<x
H xxf 2)(' ?= b?
2
00
() (0) () 0
(0) lim lim 0
xx
fx f x
f
xx
+
?→+ ?→+
?? ? ?
′ ==
??
=
2
00
() (0) () 0
(0) lim lim 0
xx
fx f x
f
xx
?
?→? ?→?
?? ?? ?
′ ==
??
=
V? b ||2)(' xxf =
?N¤?
2, 0,
''( ) 2, 0,
0
x
fx x
x
>?
?
=? <
?
?
=
?
?i b
?
^?
H2>n
()
0, 0,
()
0
n
x
fx
x
≠
?
=
?
=
?
?i b
4
! ?iQ V±p fx()
ò [( )]fx
2
′′′ ó
1
f
x
′′′
? ???
??? ?
??
? ?
? [(ln)]fx′′ ? [ln ( )]fx′′
? [( )]fe
x?
′′′ ×
])tan(arc[ ′′xf .
3
1 )('2)')((')]'([
2222
xxfxxfxf ==
)('2)(''4)(')'2()')((''2')]'([
2222222
xfxfxxfxxxxfxf +=+=
222222 2232
[ ( )]''' 4 '''( )( ) ' (4 ) ' ''( ) 2 ''( )( ) ' 8 '''( ) 12 ''( )
2
f x xfxx x fx fxx xfx xfx=++=+ b
2
'
2
1111
''ff f
1
x xx x x
′
??
?? ???? ??
==?
?? ???? ????
?? ???? ????
''
2243
111111112
'' ' '' 'ff ff
1
f
x xxxx xxxx
′′
??
?? ????? ? ?? ?? ??
=? ? = +
?? ????? ? ?? ?? ????
?? ????? ? ?? ?? ????
x
6554
1 1 14 12 16 1
fffff
x xxxxxxx
′′′
??
?? ?? ?? ?? ??
′′′ ′′ ′′ ′=????
?? ?? ?? ?? ????
?? ?? ?? ?? ??
??
x
86
2
6
11 1 1
66fxfxf
x xx
??
?? ?? ??
′′′ ′′ ′=? + +
?? ?? ????
?? ?? ??
??
x
b
3 ()
( )
x
xf
xxfxf
ln'
)'(lnln')]'(ln[ == ,
() ( ) ( ) ( )
22
ln'ln'')'(ln')'(lnln''
')]'(ln[
x
xfxf
x
xxfxxxf
xf
?
=
??
= b
4
)(
)('
)]'([ln
xf
xf
xf = ,
( )
)(
)(')()(''
')]'([ln
2
2
xf
xfxfxf
xf
?
= b
5 )(')')((')]'([
xxxxx
efeeefef
?????
?==
2
[ ( )]'' ''( )( ) ' ( ) ' '( ) ''( ) '( )
xxxxxxxxxx
f e efe e e fe e fe efe
?????????
=? ? = +
?
x
,
22
[ ( )]''' '''( )( ) ' ( ) ' ''( ) ''( )( ) ' ( ) ' '( )
xxxxxxxxxx
f eefeeefeefeeefe
????? ?????
=+++
?
x
32
'''( ) 3 ''( ) '( )
xx xxx
efe efe efe
??????
=? ? ? b
6
2
'(arctan )
[ (arctan )]' '(arctan )(arctan ) '
1
f x
fxf xx
x
==
+
,
22
22
(1 ) ''(arctan )(arctan ) ' (1 )' '(arctan )
[ (arctan )]''
(1 )
x fxxxf
fx
x
+?
=
+
x
22
''(arctan ) 2 '(arctan )
(1 )
f xxf x
x
?
=
+
b
5 ?¨ Leibniz
T9
?
()
(0)
n
y
ò xy tanarc=
ó yx= arcsin b
3
1?
222
)1(
2
'',
1
1
'
x
x
y
x
y
+
?=
+
=
7 0x = V ¤ 0)0('',1)0(' == yy b
?
T
H p ¨?
?
¤? 1)1('
2
=+ xy x n 1n>
∑
=
+?
=+
n
k
kknk
n
xyC
0
)(2)1(
0)1(
?i?
Te?1 0'')'1(
2
=+ x
87
(1) 2 () (1)
(1)
(1 ) 2 2 0
2
nn n
nn
yxnyx y
+?
?
++ ?+ ?=
[ }?¤??w
T 0=x
)0()1()0(
)1()1( ?+
??=
nn
ynny
V7¤?
1
2
()
(1) ( 1)!, ;
(0)
0,
n
n
nn
y
n
?
?
?
??
=
?
?
?
1
?
1}
? b
2?
13 3
2222
2
1'
'(1 ),''( )(1 )(1 )' (1 )
21
xy
yxy x xxx
x
?? ?
=? =? ? ? = ? =
?
7 0=x
V¤ O b ?
T
H
p ¨?
?
¤?
0)0('',1)0(' == yy '')1('
2
yxxy ?= '')1('
2
yxxy ?= x
n 1n≥
∑∑
=
+?
=
+?
?=
n
k
kknk
n
n
k
kknk
n
xyCxyC
0
)(2)2(
0
)()1(
)1()(
'
)()1()(2)2()()1(
)1(2)1(
nnknnn
ynnxnyxynyxy ????=+
+++
(1) () (2) 2 (1) ()
(1 ) 2 ( 1)
nnn n n
xynyy xxnyny
++ +
+= ?? ??
[ }?¤??w
T 0=x
)0()0(
)(2)2( nn
yny =
+
V7¤?
2
()
[( 2)!!]
(0)
0
n
nn
y
n
? ?
=
?
?
1
?
1}
? b
6 /
?f
?p
2
2
dy
dx
ò exy
xy
2
2
0
+
?=; ó 0)tan( =?+ xyyx ;
? 20yxxysin ln+=; ?
33
30xy axy+ ?=.
3
1?
T
H p?μ x
88
0'2)'2()'()'(
222
22
=??+=?+
++
yxxyyxeyxyxe
yxyx
p?¤? x
)'
=
22
( )'(2') (2')'(2
xy xy
exyxye xy xyxy
++
+++ +?+
22
22
(2 ') (2 '') 2 4 ' '' 0
xy xy
exye yyxyxy=+++???
V73
2
22
2
2
])'('442[2'4
''
xe
yxyxeyxy
y
yx
yx
?
+++?+
=
+
+
?
2
2
2
)(2
'
xe
eyx
y
yx
yx
?
?
=
+
+
b
2?
T
H p?μ x
x
0')'1)((sec)'()')((sec
22
=??++=?++ xyyyyxxyyxyx
p?¤?
22
2sec ( ) tan( )( )'(1 ') sec ( )(1 ')' ' ( ')'x yxyxyy xyyyxy+++++++??
2
2sec()tan()(1')sec()'2''xy xy y xyy yxy=+++++??0=
V73
)(sec
'2)'1)(tan()sec(2
''
2
2
yxx
yyyxyx
y
+?
?+++
=
?
)(sec
)(sec
'
2
2
yxx
yyx
y
+?
?+
= b
3?
T
H p?μ x
0'lncos2sin'2 =?+++ y
y
x
yxyxy
p?¤? x
0'')'(
'
2sin2cos'4sin''2
2
2
=?+??+?+ y
y
x
y
y
x
y
y
xyxyxy
89
V73
xyxy
yxyyxyyxy
y
sin2
)'('2cos'4sin2
''
2
223
+
+??
=
?
xyx
yyxy
y
sin2
lncos2
'
2
+
+
?= b
4?
T
H p?μ x
x
0'33'33
22
=??+ axyayyyx
p?¤?
0''3'6''3)'(66
22
=??++ axyayyyyyx
V73
2
2
'2)'(22
''
yax
ayyyx
y
?
?+
=
?
axy
xay
y
?
?
=
2
2
' b
7 /
?
??
T¥f
?p
dy
dx
2
2
ò
xat
ybt
=
=
?
?
?
2
3
,
,
ó
xat t
yat t
=
=
?
?
?
cos ,
sin ,
?
xt t
yt t
=?
=
?
?
?
(sin)
cos ,
1 ,
?
xa
yb
t
t
=
=
?
?
?
?
e,
e,
?
xt
yt
=+
=?
?
?
?
1
1
,
,
×
?
?
?
=
=
.cos
,sin
bty
atx
3
1
ta
b
at
abtatbt
at
atbtatbt
dx
yd
23
2
32
2323
2
2
4
3
)2(
)2)(3()2)(6(
])'[(
')'()'()'(')'(
=
?
=
?
= b
2
2
23
( sin ) ''( cos ) ' ( sin ) '( cos ) ''
[( cos )']
dy at t at t at t at t
dx at t
?
=
90
33
222 2
33
(2cossin)(cossin)(sincos)(2sincos
(cos sin )
( 2)(sin cos ) 2
(cos sin ) (cos sin )
a t at t a t at t a t at t a t at t
attt
tttt
a ttt a ttt
)? ?++ +
=
?
++ +
==
??
b
3
2
23
( cos ) ''[( (1 sin )]' ( cos ) '[ (1 sin )]''
[(1 sin )]'
dytttttttt
dx t t
?? ?
=
?
3
2
3
( 2sin cos )(1 sin cos ) (cos sin )( 2cos sin )
(1 sin cos )
22sin cos
(1 sin cos )
tt t tt t tt t tt t
tt t
tttt
tt t
?? ?? ?? ?+
=
??
+? ?
=
??
b
4
2
23
( ) ''( ) ' ( ) '( ) ''
[( ) ']
tt tt
t
d y be ae be ae
dx ae
??
?
?
=
3
23 2
2
tt tt
t
t
be e be e b
e
ae a
??
?
??
==
?
b
5
2
2
3
( 1 ) ''( 1 ) ' ( 1 ) '( 1 ) ''
[( 1 ) ']
dy t t t t
dx
t
?+??+
=
+
3
3
2
33
11
(2 1 ) 2(1 )
4( 1 ) (2 1 ) 2( 1 )[4( 1 ) ]
tt
tt tt
???
?
=? +=
??
?+ ?+
??
? b
6
2
2'3
(cos ) ''(sin ) ' (cos ) '(sin ) ''
(sin )
d y bt at bt at
dx at
?
=
23
(sinsin coscos)
cos
b a at bt b at bt
aat
??
=
23
(sin sin cos cos )
cos
b a at bt b at bt
aat
+
=? b
8 ?¨Qf
?¥p?
T
dx
dy y
=
′
1
£
ü
ò
32
2
)'(
''
y
y
dy
xd
?= ;
ó
dx
dy
yy
y
3
3
2
5
3
=
′′ ? ′ ′′′
′
()
()
.
£
1
2
2
1
() ()
'
dx d dx d
dy dy dy dy y
==
22 2
1' 1' '1 '
(') (') (') ' (')
dy dy dx y y
y dy y dx dy y y y
=? =? =? ? =? b
3
2
()
32
332
''
() [ ]
'
dx d dx d y
dy dy dy dy
y
==?
34
1'' '
3
(') (')
dy y dy
ydy ydy
=? +
'
22
34 34
1 '' '' ' ''' 1 3( '') 1 3( '') ' '''
3
(') (') (') ' (') ' (')
dy dx y dy dx y y y y y
ydxdy ydxdy y y y y y
?
=? + =? ? + ? = b
5
91
9 p/
f
?¥ú¨±s
ò ,tan
3
xxy ?= p dy
2
ó yx
x
=
?4
e p dy
4
? y
x
x
=
+1
2
p dy
2
?
y
x
x
=
?
sec
2
1
p dy
2
? yx x= sin 3 p dy
3
× yx
x
= p dy
2
?
y
x
x
=
ln
p d y
n
ù yx x
n
= cos 2 p . dy
n
3
1
2
2
3
1
(tan)(1sec)
3
dy x x x dx
?
=? ?
2
2
3
1
(tan)tan
3
x xx
?
=? ? dx
52
222
33
21
[ ( tan ) (1 sec ) ( tan ) (2 tan sec )]
93
dy x x x x x x xdx
??
=? ? ? ? ?
2
42
2
5
3
2 tan 6sec tan ( tan )
9(tan )
xxxx
dx
xx
+?
=
?
b
2
4
44()(4)4
4
0
[()() ]
kkxk
k
dy C x e dx
??
=
=
∑
4
44
4
0
4!
(1)
(4 )!
kkk
k
Cx e
k
???
=
=?
?
∑
4x
d
4234
)24967216( dxexxxx
x?
+?+?= b
3 dx
xx
dx
x
xxx
x
dy
22
2
2
2
1
1
11)2(
12
1
+
?=
?+???
+
=
2
22
33
32
22 32
22
22
[]
1
2(1 ) (1 )
xx
d y dx dx
xx
xx xx
+
=+ =
+
++
b
4
2
13 3
22
2
tan sec 1 sec (2 ) sec [( 1) tan ]
[]
2
(1) (1) (1)
xx xx xx xx
dy dx dx
??
=?? =
?? ?
?
2
3
2
2
sec tan [( 1) tan ] sec [2 tan ( 1)sec 1]
(1)
xxx xx xxxx x
dy
x
?
??+ +? ??
=
?
?
?
?
2
2
5
2
2
3sec[( 1)tan ](2)
2
(1)
xx x x x
dx
x
?
????
??
?
?
?
?
92
22 2 2 2
2
5
2
2
sec [( 1) (1 2 tan ) 2 ( 1) tan 2 1]
(1)
xx x xx x x
dx
x
?+ ? ? ++
=
?
b
5
333
27(sin 3 cos3 )[ (sin 3 ) ''' 3 '(sin 3 ) '']dy x x x x dx=+ x xxd=? + x b
6 dxxxdxxededy
xxxxx
)ln1()ln1(
lnln
+=+==
2 22
1
[( )'(1ln) (1ln)'] [(1ln) ]
xx x
d y x x x x dx x x dx
x
=+++ =++ b
7
n
n
k
knkk
n
n
dx
x
xCyd
∑
=
?
=
0
)()(
)
1
()(ln
1
1 1
1
(1) ! ! ( 1)! ( )!
[ln (1) (1) ]
!( )!
n n
knk
nk
k
nnknk
n
x dx
xknkxx
??
+ ?+
=
??
=+ ??
?
∑
1
1
(1) ! 1
ln
n n
n
n
k
n
x dx
xk
+
=
? ??
=?
??
??
∑
b
8
n
n
k
kknnk
n
n
dxxxCyd
∑
=
?
=
0
)()(
)2(cos)(
0
!!
()[2cos(2 )]
!( )! ! 2
n
kk
k
nn k
n
x xd
knk k
π
=
=+
?
∑
x
2
2
0
2cos(2 )
2
(!)
(!)( )!
kk
n
n
k
k
xx
nd
knk
x
π
=
+
=
?
∑
b
10p ?
2
()
x
de
ò x
^1M
; ó )(tx ?=
^?WM
.
3
1 dxedxeed
xxx
== )'()(
222
)'()()( dxedxedxeded
xxxx
=== b
2 dttedxedxeed
txxx
)(')'()(
)(
?
?
===
2() ()2
() ( '())[ '()]'
xt t
de de tdt e t dt
??
==
{ }
() 2 2
[ '( )] ''( )
t
ett
?
??=+dt b
11
! ?iQ V±O b fu() gu() gu()> 0
ò? xu tan=
Hp d f
2
ó? u= v av x= ln
Hp dg
2
93
? dfugu
2
[()()] ? dgu
2
[ln ( )]
?
?
?
?
?
?
?
)(
)(
2
ug
uf
d
3
1 xdxxfdxxuufdf
2
sec)(tan')(')(' ==
222
''( )[ '( )] '( ) ''( )d f f u u x dx f u u x dx=+
2
2
42
[ "(tan )sec 2 '(tan )sec tan ]f xxfxxxd=+ x b
2 xvu ln==
11 1
'( ) '( ln )
2ln 2 ln
dg du dv
dg dx g u dx g x dx
du dv dx x
x xx
== =
22
2
"( )
'( )(2 ln ) '
[]
2ln (2ln)
du dv
gu
gu x x
dv dx
dg dx
xx xx
=?
2
22
11
'( )[2 ln 2 ( )]
"( )
2ln
(2 ln ) (2 ln )
gu x x
gu
x
x
dx
xx xx
??
+?
??
=?
??
??
2
3
2
2
"(ln)ln '(ln)(12ln)
4ln
gxxgx x
dx
xx
?+
= b
3 duugufugufugufd )](')()()('[)]()([ +=
222
)]'()()()('[)](')()()('[)]()([ duugufugufudugufugufugufd +++=
22
[ '()() () '()] [ "()() 2 '() '() () "()]f ugu fug u du f ugu f ug u fug u du=+ ++ + b
4 du
ug
ug
ugd
)(
)('
)]([ln =
2
2222
2
'() '() '() "()() ( '())
[ln ( )] [ ]'
() () () ()
gu gu gu g ugu gu
dgu du du du du
gu gu gu g u
?
=+ =+ b
5 du
ug
ugufuguf
ug
uf
d
)(
)(')()()('
)(
)(
2
?
=
?
?
?
?
?
?
94
2
2
2
2
2
)(
)(')()()('
)(
)(')()()('
)(
)(
du
ug
ugufuguf
ud
ug
ugufuguf
ug
uf
d
′
?
?
?
?
?
? ?
+
?
=
?
?
?
?
?
?
2
2
'( ) ( ) ( ) '( )
()
fugu fugu
du
gu
?
=+
2 2
2
3
"() () ()() "() 2 '() '()() 2 ()( '())
()
f ug u fugug u f ug ugu fu g u
du
gu
?? +
b
12. ?¨
?DB,E£
ü
x
n
n
n
x
n
e
x
ex
1
1
)(
1
1
)1(
+
?
?
=
?
?
?
?
?
?
?
?
b
£ ?
H1=n
xxx
n
x
n
e
xx
eeex
1
2
11
)(
1
1
1
)'
1
()'()(
?
===
?
5? ? b L
!
H
5?? ? b5?
H
kn ≤
1+= kn
() ()
11 11
1() 1
1
()()' ()'
kk
nn k k k
xx xx
xe xe kxe xe
x
??
??? ?
==+
??? ?
??? ?
()
11 11
12(1)
1
(1) (1)
()
k
kk
kkk
xx x
kx e x e k e e
xx
?
???
+
x
′ ′
??? ? ?
??
=? =?
??? ? ?
??? ? ?
?
?
?
11111
2
(1) (1) (1) 1 (1)
()
kkk
xxx
k
keke e
xxx x
?+
++ +
??
??? ?
=? +?=
??
??
1
2
x
e
59? ? b?
?DB,E V?' 5
?μ??
??? ? b
95