Câu III, đ s 1, th sc trưc k thi (THTT)
Bi ton
( )
x
x
I
x
π
+
+
=
+
∫
Hưng d"n
a a
b b
α
α
=
a a a
b
b b
b
= −
Gii
( )
( ) ( )
x
x
x
x x
x
+
+
+
= + − +
+
( ) ( ) ( )
x x x= + + − +
( ) ( ) ( )
x x x x= + + + − +
( )
( ) ( ) ( )
x
x
I x dx x x dx x dx
x
π π π π
+
+
= = + + + − +
+
∫ ∫ ∫ ∫
( )
x
x
I I I I
x
π
+
+
= = + −
+
∫
( )
I x dx
π
= +
∫
x t x t t
π π
= − ⇒ = − =
÷
dx dt
= −
Đi cn
( )
I x dx I
π
= + =
∫
I I⇒ − =
!
( )
I x x dx
π
= +
∫
t x
= +
dt xdx
=
Đi cn
( )
I x x dx tdt
π
= + =
∫ ∫
dt
u t
du
t
dv dt
v t
=
=
⇒
=
=
"
I t t dt t t t
e
= − = − = − =
∫
#$%
( )
"
x
x
I
x e
π
+
+
= =
+
∫
π
x
t
π
x
t
π