NEB NotesNepal
Unit 9 • Class 11Mathematics (Grade 11) (Mat.401)

Pair of Straight Lines

सरल रेखाको जोडी

Homogeneous equation of second degree ax² + 2hxy + by² = 0, angle between pair of lines, condition for perpendicularity and coincidence, angle bisectors.

Lesson Summary & Key Concepts

Comprehensive study of second-degree homogeneous equations ax² + 2hxy + by² = 0, angle between two lines, condition for perpendicularity and coincidence, and combined equation of angle bisectors.

Textbook Exercises & Solutions

Showing 5 of 5 Solved Questions
Ex 10.1Question 3• 4 Marks

Topic: Pair of Straight Lines & Homogeneous Equations

Ex 10.1Question 7• 4 Marks

Topic: Pair of Straight Lines & Homogeneous Equations

Ex 10.1Question 1• 4 Marks

Topic: Pair of Straight Lines & Homogeneous Equations

Ex 10.1Question 5• 4 Marks

Topic: Pair of Straight Lines & Homogeneous Equations

Question 5• 6 Marks

Quick Revision Takeaways

Common Exam Pitfalls to Avoid

⚠️ Common Error: Taking 2h as h directly when identifying coefficients.

✓ Correct Approach: Always divide the coefficient of xy by 2 to obtain h.

Why: In ax² + 2hxy + by² = 0, the middle coefficient is 2h.

Content Provenance & Verification
Editorial Verified & Published
Original Author / ContributorNEB Mathematics Subject Specialist
Verified BySenior Subject Specialist (TU / NEB Panel)
Curriculum Versionv1.0 (CDC 2078/2080 Grid)
Last Verified Date2026-10-23
Legitimate Official Curriculum References
Found an ambiguity, error, or updated syllabus note?