76
77
140.
Moddiy nuqta
( )
4
3
10
4
t
s t
t
= −
+
qonuniyat bilan harakatlanmoqda
(
s
(
t
)
metrda
, t
sekundda o‘lchanadi).
1) eng katta tezlanishga erishadigan (
t
0
) vaqtni;
2)
t
0
vaqtdagi oniy tezlikni;
3)
t
0
vaqtda bosib o‘tilgan yo‘lni toping.
141.
Havo shariga
t
∈
[0;10] minut oralig‘da
V
(
t
) =
t
3
+3
t
2
+2
t
+4 m
3
havo
purkalmoqda.
1) boshlang‘ich vaqtdagi havo hajmini;
2)
t
= 10
minutdagi havo hajmini;
3)
t
= 5 minutdagi havo purkash tezligini toping.
142.
Akrom shim tikish uchun buyurtma oldi. Bir oyda
x
ta shim tiksa,
p
(
x
) = – 2
x
2
+240
x
(ming so‘m) daromad qiladi.
1) daromadni eng katta qilish uchun qancha shim tikish kerak?
2) eng katta daromad necha so‘m bo‘ladi?
143
.
Funksiyaning hosilasini toping:
1)
x
e
y
3
=
; 2)
x
e
y
sin
=
; 3)
(
)
2
3
sin
+
=
x
y
; 4)
(
)
4
1
2
+
=
x
y
;
5)
1
2
2
+
−
=
x
x
y
; 6)
ln
x
y
x
=
; 7)
y
= arctg2
x
; 8)
x
e
x
x
y
⋅
⋅
=
cos
2
.
144.
( )
x
e
x
f
2
=
va
( )
2
4
+
=
x
x
g
funksiyalar uchun
( )
x
F
murakkab
funksiyani tuzing:
1)
( )
( )
(
)
x
g
f
x
F
=
;
2)
( )
( )
( )
x
g
x
f
x
F
=
;
3)
( )
( )
(
)
x
f
g
x
F
=
;
4)
( )
( )
(
)
x
g
g
x
F
=
.
145.
Murakkab funksiyaning hosilasini toping:
1)
(
)
5
2
1
+
=
x
y
; 2)
y
=lncos
x
;
3)
7
5
−
=
x
y
; 4)
(
)
tg 2
3
y
x
=
−
;
5)
y=
arctg(3
x
–4);
6*)
y=
sin(arctg2
x
);
7)
x
x
y
3
3
cos
sin
+
=
;
8*)
(
)
x
e
y
cos
sin
=
.
78
79
II BOB. INTEGRAL VA UNING TATBIQLARI
37–39
BOSHLANG‘ICH FUNKSIYA VA ANIQMAS
INTEGRAL TUSHUNCHALARI
Agar nuqta harakat boshlanganidan boshlab
t
vaqt
mobaynida
s
(
t
)
masofani o‘tgan bo‘lsa, uning oniy tezligi
s
(
t
) funksiyaning hosilasiga teng
ekanini bilasiz:
v
(
t
)=
s
'(
t
). Amaliyotda
teskari masala:
nuqtaning berilgan
harakat tezligi
v
(
t
) bo‘yicha uning bosib o‘tgan yo‘li
s
(
t
) ni topish masalasi
ham uchraydi. Shunday
s
(
t
)
funksiyani topish kerakki, uning hosilasi
v
(
t
)
bo‘lsin. Agar
s
'(
t
)=
v
(
t
) bo‘lsa,
s
(
t
) funksiya
v
(
t
) funksiyaning
boshlang‘ich
funksiyasi
deyiladi. Umuman, shunday ta’rif kiritish mumkin:
Agar (
a
;
b
)
ga tegishli ixtiyoriy
x
uchun
F
′(
x
)=
f
(
x
) bo‘lsa,
F
(
x
)
funksiya (
a
;
b
) oraliqda
f
(
x
) ning
boshlang‘ich funksiyasi
deyiladi.
1-misol.
a
– berilgan biror son va
v
(
t
)=
at
bo‘lsa,
2
1
( )
2
s t
at
=
funksiya
v
(
t
) funksiyaning boshlang‘ichidir,
chunki
s
2
( ) (
)
( ).
2
at
s t
at v t
′
′
=
=
=
2-misol.
f
(
x
)
=x
2
, x
∈
(– ∞; ∞), bo‘lsa,
3
1
( )
3
F x
x
=
funksiya
f
(
x
)
ning
(– ∞; ∞) dagi bo
shlang‘ich funksiyasi bo‘ladi, chunki
F
3
2
2
1
1
( ) (
)
3
( ).
3
3
F x
x
x
x
f x
′
=
= ⋅
=
=
ʹ
3
2
2
1
1
( ) (
)
3
( ).
3
3
F x
x
x
x
f x
′
=
= ⋅
=
=
3-misol.
2
1
( )
,
cos
f x
x
=
bunda
,
2
x
k
π
≠ + π
k
∈
Z
,
funksiya uchun
F
(
x
)=tg
x
boshlang‘ich funksiya bo‘ladi, chunki (tg
x
)'
1
2
1
( )
.
cos
tgx
x
=
4-misol.
1
( )
,
f x
x
=
x
>0, bo‘lsa,
F
(
x
)
=
ln
x
funksiya
1
x
ning boshlang‘ich