INTEGRATION BY PARTIAL
FRACTION:
• Step 1 Factorize denominator into irreducible factors
•
𝑥2
𝑥2−5𝑥+6
=
𝑑𝑥
(𝑥−3)(𝑥−2)
• CASE 1:If factors are linear put in form
𝐴
𝑥+𝑐
+
𝐵
𝑥+𝑑
and find A
and B
•
𝑑𝑥
𝑥−3 (𝑥−2)
=
𝐴
𝑥−3
ⅆ𝑥 +
𝐵
𝑋−2
ⅆ𝑥
• CASE 2: If factors are linear but squared put in form:
•
𝑑𝑥
(𝑥−2)(𝑥+1)2 =
𝐴
𝑥−2
dx+
𝐵
(𝑥+1)
dx+
𝐶
(𝑥+1)2dx
•CASE 3: If factors are quadratic put in form:
•
𝑑𝑥
𝑥−1 𝑥2−3𝑥−2
=
𝐴
(𝑥−1)
dx+
𝐵𝑥+𝐶
𝑥2−3𝑥−2
dx
•CASE 4: If factors are quadratics but squared put in
form:
•
𝑑𝑥
(𝑥−1)(𝑥2−3𝑥−2)2
•=
𝐴
(𝑥−1)
dx +
𝐵𝑥+𝐶
𝑥2−3𝑥−2
dx +
𝐷𝑥+𝐸
(𝑥2−3𝑥−2)2dx
EXAMPLE:
•
3𝑥+1
𝑥2−𝑥−6
ⅆ𝑥
•
3𝑥+1
𝑥2−𝑥−6
=
3𝑥+1
(𝑥+2)(𝑥−3)
• Let
3𝑥+1
(𝑥+2)(𝑥−3)
=
𝐴
(𝑥+2)
+
𝐵
(𝑥−3)
------eq 1
• Multiply by (𝑥 + 2)(𝑥 − 3) on both sides
• 3𝑥 + 1=A(x-3)+B(x-2) -------eq 2
• Factorization:
• 𝑥2 − 𝑥 − 6
• 𝑥2 − 3𝑥 + 2𝑥 − 6
• 𝑥 𝑥 − 3 + 2(𝑥 −
3)
• Put x-3 =0
• So x=3
• Put value of x in eq 2
• 3(3)+1=A(3-3)+ B (3+2)
• 10=5B
• B=2
• Put x+2=0
• So x=-2
• Put value of x in eq 2
• 3(-2)+1=A(-2-3)+ B(-2+2)
• -5=A(-5)
• A=1
• Put values of A and B in eq 1
•
3𝑥+1
(𝑥+2)(𝑥−3)
=
𝐴
(𝑥+2)
+
𝐵
(𝑥−3)
------eq 1
•
3𝑥+1
(𝑥+2)(𝑥−3)
=
1
𝑥+2
+
2
𝑥−3
• Now apply integration
•
3𝑥+1
(𝑥+2)(𝑥−3)
=
1
𝑥+2
ⅆ𝑥 + 2
1
𝑥−3
ⅆ𝑥
=2ln 𝑥 − 3 + ln 𝑥 + 2 +c
(here c is constant)
•THANKS FOR UR PRECIOUS
TIME…

Integration by partial fraction

  • 2.
  • 4.
    • Step 1Factorize denominator into irreducible factors • 𝑥2 𝑥2−5𝑥+6 = 𝑑𝑥 (𝑥−3)(𝑥−2) • CASE 1:If factors are linear put in form 𝐴 𝑥+𝑐 + 𝐵 𝑥+𝑑 and find A and B • 𝑑𝑥 𝑥−3 (𝑥−2) = 𝐴 𝑥−3 ⅆ𝑥 + 𝐵 𝑋−2 ⅆ𝑥
  • 5.
    • CASE 2:If factors are linear but squared put in form: • 𝑑𝑥 (𝑥−2)(𝑥+1)2 = 𝐴 𝑥−2 dx+ 𝐵 (𝑥+1) dx+ 𝐶 (𝑥+1)2dx
  • 6.
    •CASE 3: Iffactors are quadratic put in form: • 𝑑𝑥 𝑥−1 𝑥2−3𝑥−2 = 𝐴 (𝑥−1) dx+ 𝐵𝑥+𝐶 𝑥2−3𝑥−2 dx
  • 7.
    •CASE 4: Iffactors are quadratics but squared put in form: • 𝑑𝑥 (𝑥−1)(𝑥2−3𝑥−2)2 •= 𝐴 (𝑥−1) dx + 𝐵𝑥+𝐶 𝑥2−3𝑥−2 dx + 𝐷𝑥+𝐸 (𝑥2−3𝑥−2)2dx
  • 9.
    EXAMPLE: • 3𝑥+1 𝑥2−𝑥−6 ⅆ𝑥 • 3𝑥+1 𝑥2−𝑥−6 = 3𝑥+1 (𝑥+2)(𝑥−3) • Let 3𝑥+1 (𝑥+2)(𝑥−3) = 𝐴 (𝑥+2) + 𝐵 (𝑥−3) ------eq 1 •Multiply by (𝑥 + 2)(𝑥 − 3) on both sides • 3𝑥 + 1=A(x-3)+B(x-2) -------eq 2 • Factorization: • 𝑥2 − 𝑥 − 6 • 𝑥2 − 3𝑥 + 2𝑥 − 6 • 𝑥 𝑥 − 3 + 2(𝑥 − 3)
  • 10.
    • Put x-3=0 • So x=3 • Put value of x in eq 2 • 3(3)+1=A(3-3)+ B (3+2) • 10=5B • B=2 • Put x+2=0 • So x=-2 • Put value of x in eq 2 • 3(-2)+1=A(-2-3)+ B(-2+2) • -5=A(-5) • A=1
  • 11.
    • Put valuesof A and B in eq 1 • 3𝑥+1 (𝑥+2)(𝑥−3) = 𝐴 (𝑥+2) + 𝐵 (𝑥−3) ------eq 1 • 3𝑥+1 (𝑥+2)(𝑥−3) = 1 𝑥+2 + 2 𝑥−3 • Now apply integration • 3𝑥+1 (𝑥+2)(𝑥−3) = 1 𝑥+2 ⅆ𝑥 + 2 1 𝑥−3 ⅆ𝑥 =2ln 𝑥 − 3 + ln 𝑥 + 2 +c (here c is constant)
  • 12.
    •THANKS FOR URPRECIOUS TIME…