11th Class Maths Chapter 5 Notes Partial Fractions – Solution | Get No
11th Class Maths Chapter 5 Notes Partial Fractions Solutiion help students understand one of the most calculation-heavy chapters in 11th Class Mathematics. This chapter teaches how to break a complicated rational function into simpler fractions, a skill that becomes essential later in integration and calculus.
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These notes follow the Punjab Textbook Board syllabus (Mathematics Part-I) and explain every exercise with clear, step-by-step examples so students can practice confidently before their board exams.
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What Are Partial Fractions?
We already know how to combine two or more rational fractions into a single fraction. For example:
1/(x − 1) + 2/(x + 2) = 3x / [(x − 1)(x + 2)]
Partial fractions work the opposite way. To express a single rational function as a sum of two or more simpler rational functions is called resolving it into partial fractions. This reverse process is exactly what 11th Class Maths Chapter 5 Notes Partial Fractions Solutiion focus on teaching.
Rational Fraction and Its Types
A rational fraction is the quotient of two polynomials P(x)/Q(x), where Q(x) ≠ 0 and P(x), Q(x) have no common factors. There are two types:
1. Proper Rational Fraction
A fraction is proper when the degree of P(x) is less than the degree of Q(x). For example, 3/(x + 1) and (2x − 5)/(x² + 4) are proper rational fractions.
2. Improper Rational Fraction
A fraction is improper when the degree of P(x) is equal to or greater than the degree of Q(x). For example, x/(2x − 3) is an improper rational fraction. In this case, long division is done first to reduce it into a polynomial plus a proper fraction before applying partial fraction rules.
For more foundational algebra concepts, check the [internal link] for Chapter 4 notes on Quadratic Equations before starting this chapter.
Case 1: Denominator with Non-Repeated Linear Factors
When the denominator breaks into distinct linear factors, each factor gets its own constant numerator. For example, to resolve 1/(x² − 1):
- Factor the denominator: 1/[(x + 1)(x − 1)]
- Write it as A/(x + 1) + B/(x − 1)
- Clear the denominators and solve for A and B by substituting convenient values of x
This gives the result: −1/[2(x + 1)] + 1/[2(x − 1)]
This is the simplest and most common type covered in 11th Class Maths Chapter 5 Notes Partial Fractions Solutiion, and it forms the foundation for the more advanced cases.
Case 2: Denominator with Repeated Linear Factors
When a linear factor repeats, such as (x − 1)³, the partial fraction must include a term for every power of that factor, not just one. For example:
(2x² − 3x + 4)/(x − 1)³ = A/(x − 1) + B/(x − 1)² + C/(x − 1)³
Students find the constants by:
- Substituting the repeated root directly to find the last constant
- Comparing coefficients of x² and x for the remaining constants
This method appears frequently in Exercise 5.2 and needs careful attention to avoid calculation mistakes.
Case 3: Denominator with Non-Repeated Quadratic Factors
Sometimes the denominator contains a quadratic expression that cannot be factored further, such as x² + 1 or x² + 4. In these cases, the numerator over that quadratic factor is written as (Ax + B) instead of a single constant.
For example, resolving 1/[(x² + 1)(x + 1)] gives:
(−x + 1)/[2(x² + 1)] + 1/[2(x + 1)]
This distinction is important — using only a constant numerator (instead of Ax + B) over a quadratic factor is one of the most common mistakes students make in this chapter.
Case 4: Denominator with Repeated Quadratic Factors
The most advanced case combines repeated quadratic factors, such as (x² + x + 1)². Here, the numerator for each power of the quadratic factor takes the form (Ax + B), similar to Case 3, but repeated for each degree of the factor.
For example:
(x³ + 2x + 2)/(x² + x + 1)² = (Ax + B)/(x² + x + 1) + (Cx + D)/(x² + x + 1)²
Solving these requires comparing coefficients of x³, x², x, and the constant term, which makes this case the lengthiest in the entire chapter.
Step-by-Step Method to Solve Partial Fractions
Following a clear method makes 11th Class Maths Chapter 5 Notes Partial Fractions Solutiion much easier to apply during exams:
- Check whether the fraction is proper or improper. If improper, divide first.
- Factor the denominator completely into linear and quadratic factors.
- Write the correct form of partial fractions based on the type of factor (linear, repeated linear, quadratic, or repeated quadratic).
- Multiply both sides by the original denominator to clear fractions.
- Find the unknown constants by substituting convenient values of x or by comparing coefficients.
- Substitute the constants back into the partial fraction setup for the final answer.
Common Techniques Used to Find Constants
There are two main techniques students use throughout this chapter:
- Substitution Method: Put in values of x that make one or more factors zero, instantly solving for a constant. This works fastest for linear, non-repeated factors.
- Comparing Coefficients: After expanding both sides, match the coefficients of matching powers of x (like x³, x², x, and constants). This is required whenever substitution alone cannot solve all constants, especially with quadratic or repeated factors.
Most board exam questions combine both techniques within a single problem, so mastering each one separately is important before attempting mixed exercises.
Why This Chapter Matters for Board Exams
Partial fractions frequently appear in board papers from Lahore Board, Gujranwala Board, and other boards across Punjab. Having reliable 11th Class Maths Chapter 5 Notes Partial Fractions Solutiion available helps students:
- Practice all four cases with fully worked solutions
- Avoid common mistakes with repeated and quadratic factors
- Understand long division for improper fractions
- Build a strong base for integration techniques used in later chapters
For a complete set of resources, visit [internal link] to browse full 11th Class Mathematics notes covering every chapter.
Tips to Score Well in This Chapter
- Always check if the fraction is proper before starting — dividing first saves time
- Memorize the correct partial fraction form for each type of factor
- Practice substitution for quick constants, then use coefficient comparison for the rest
- Solve previous board papers to see how this chapter is typically tested
- Double-check your final answer by adding the partial fractions back together
FAQs
Q1. What is the difference between proper and improper rational fractions?
A rational fraction is proper when the numerator’s degree is smaller than the denominator’s degree. It’s improper when the numerator’s degree is equal to or greater than the denominator’s degree, requiring long division first.
Q2. Where can I find complete 11th Class Maths Chapter 5 Notes Partial Fractions Solutiion?
Complete 11th Class Maths Chapter 5 Notes Partial Fractions Solutiion with all exercises solved step by step are available for free on TaleemWorld.com, covering every case from linear to repeated quadratic factors.
Q3. How many types of partial fractions are there?
There are four main types: non-repeated linear factors, repeated linear factors, non-repeated quadratic factors, and repeated quadratic factors. Each type uses a different form for writing the numerator.
Q4. Why do we use Ax + B for quadratic factors instead of just A?
A quadratic factor like x² + 1 cannot be broken down further into real linear factors, so its numerator must include a variable term (Ax + B) to correctly represent all possible values, unlike simple linear factors.
Q5. What is the easiest way to find constants in partial fractions?
Substituting values of x that make a factor equal to zero is the fastest method for linear factors. For quadratic or repeated factors, comparing coefficients of matching powers of x is usually necessary.
Q6. Do improper fractions need extra steps before partial fraction resolution?
Yes. If the numerator’s degree is equal to or higher than the denominator’s degree, you must perform polynomial long division first, then apply partial fraction rules only to the remaining proper fraction part.
