Mathematics • Class 11
Linear Inequalities - Class 11
Master Linear Inequalities through focused practice that strengthens conceptual understanding, problem-solving skills, and the ability to recognize common traps and misconceptions. Explore challenging questions designed to develop deeper reasoning and confident application of key ideas.
Overview
This chapter introduces the concept of Linear Inequalities and their applications in real-life scenarios. Learn how to solve and graph inequalities in one and two variables and interpret solutions geometrically.
Why This Chapter Matters
- Linear Inequalities are essential for understanding optimization problems, decision-making, and other mathematical modeling concepts. They form the basis of linear programming and are widely used in various fields.
Real-Life Applications
- Modeling and solving optimization problems in economics and business.
- Determining feasible solutions in linear programming.
- Solving problems involving constraints in engineering and sciences.
Skills You Will Learn
- Solving linear inequalities in one and two variables.
- Graphically representing inequalities on a number line and coordinate plane.
- Applying linear inequalities to real-world problems and optimization scenarios.
Core Concepts to Master
Sign Flipping Rule
Inequality sign reverses when multiplying or dividing both sides by a negative number; failure causes sign errors.
Wavy Curve (Method of Intervals)
Determines sign of rational expressions; critical points must be marked, alternating signs from right to left starting positive.
Even Multiplicity Roots
Roots with even exponents do not change the sign of the expression across the critical point; a common trap.
Denominator Restriction
Denominator can never be zero; critical points from the denominator must always be excluded from the solution set.
Modulus Inequality Logic
Transform |x| < a to -a < x < a and |x| > a to x > a or x < -a; mishandling cases is fatal.
Cross Multiplication Trap
Never cross-multiply variables unless the sign is known; bring terms to one side and use common denominators instead.
Closed vs Open Intervals
Include critical points for 'equal to' (≥, ≤) but strictly exclude for denominator roots; confusion here loses marks.
System of Inequalities
Multiple inequalities must satisfy the intersection of all individual solution sets; use number line overlap carefully.
Graphical Feasible Region
In 2D, the test point (0,0) determines the half-plane; axis-crossing checks are vital for boundary lines.
Modulus Sign Dependency
When multiple modulus terms exist, define critical points and solve inequality within each specific interval partition.
Concept Collisions Used by Examiners
Competitive examinations rarely assess concepts in isolation. Instead, examiners intentionally combine multiple concepts from this and related chapters to create higher-order questions that test conceptual reasoning, analytical thinking, and problem-solving ability. The concept collision patterns below represent the combinations most frequently used while designing questions for this chapter.
Exam Coverage
Understand how this chapter is tested across major competitive examinations.
JEE Advanced
India · Competitive Exam · Undergraduate
JEE Main
India · Competitive Exam · Undergraduate
BITSAT
India · Competitive Exam · Undergraduate
IISER Aptitude Test (IAT)
India · Competitive Exam · Undergraduate
NEST
India · Competitive Exam · Undergraduate
ISI Admission Test
India · Competitive Exam · Undergraduate
CMI Entrance
India · Competitive Exam · Undergraduate
IOQM / INMO
India · Olympiad · High School
SAT Math
United States · Curriculum · High School
A-Level Mathematics
United Kingdom · Curriculum · Advanced Level
A-Level Further Mathematics
United Kingdom · Curriculum · Advanced Level
IB Mathematics AA HL
International · Curriculum · IB Diploma
Singapore A-Level Mathematics
Singapore · Curriculum · Advanced Level
Cambridge International A-Level Mathematics
International · Curriculum · Cambridge
International Mathematical Olympiad (IMO)
International · Olympiad · International
Practice Questions
Strengthen your understanding by solving carefully selected questions from this chapter.
Evaluate the following limit:
Find the complete set of real values of that satisfy the inequality:
Let be a continuous function satisfying the differential equation for all . If , then the value of is
Let be a matrix where is the number of integers satisfying the inequality for . Let be the matrix such that for any matrix , the product represents the matrix obtained by first swapping the first and second rows of , and then swapping the second and third rows of the resulting matrix. Consider the system of linear equations , where and . If is the unique solution to the system, find the value of .
Find the complete solution set for satisfying the inequality:
Let be a real-valued continuous function on its maximal domain , satisfying the differential equation where is a constant. If for some positive constant , find the value of .
Let be a real-valued continuous function defined on satisfying the implicit equation If is the set of all for which is strictly decreasing, then is equal to:
Find the complete solution set for satisfying the inequality:
Let be defined as , where denotes the fractional part of . Let be the set of all points such that is differentiable at and . Find the sum of all rational elements in .
Let be the set of all integers that satisfy the inequality: Find the number of elements in .
Let be the set of all points satisfying the following constraints: Find the maximum value of the objective function for .
Let for . If for , evaluate the infinite series .
Let be a function defined by . Let denote the inverse function of . Determine the value of , if it exists.
Let for , where denotes the greatest integer less than or equal to . Find the number of points of local extrema of in the interval .
Let be a differentiable function on the interval that satisfies the differential equation and the initial condition . The value of is:
Let . Let be the sum of all where attains a local maximum, and be the sum of all where attains a local minimum. If is non-differentiable at exactly points in its domain, find the value of .
Let . A subset of three distinct elements is chosen from . Find the number of such subsets for which the lines and are concurrent, where the family of lines is given by
Consider the linear programming problem: Minimize subject to the constraints: The minimum value of is:
Let , where denotes the greatest integer function. Let be the sum of the squares of the -coordinates of all points of local extremum of in the interval . Then the value of is
Evaluate the following limit:
Let be the total area of the regions bounded by the curve and the -axis. Find the value of .
Let , where , , and denotes the greatest integer function. If the right-hand limit and the left-hand limit (where is a finite real number), find the value of .
Find the set of all real values of satisfying the inequality: where denotes the greatest integer function.
Let be the set of all real values of satisfying the equation Find the sum of the squares of all elements in .
Let be defined as If is the set of all points of local extrema of , then the value of is:
Let be the set of all satisfying the inequality Find the set .
Let be a matrix given by . If there exists a matrix with real entries such that , find the sum of all possible real values of .
Let be the circle and be the circle . Let be the set of all points on such that the chord of contact of with respect to intersects at points and . If the coordinates of both and must satisfy the strict inequality , then the number of points on that are NOT in is:
Let be a real-valued differentiable function defined on the interval satisfying the differential equation If , then the set of all possible values of is:
Let . An integer is chosen uniformly at random from . Given , an integer is chosen uniformly at random from the set . The probability that is
Let . Find the solution set of the inequality in the domain , where denotes the greatest integer less than or equal to , and is the derivative of .
Let be the set of points in the Cartesian plane satisfying the following conditions: What is the area of the region ?
Let be the greatest real number satisfying the inequality Consider the following system of linear equations in variables : \begin{align*} x + y + z &= 1 \ x + 2y + 2z &= 2 \ x + 3y + (\alpha + 1)z &= 4 \end{align*} Which of the following statements is true regarding the system?
Find the complete set of values of for which the function is monotonically increasing.
Let . Let be a function satisfying the inequality for all . If and , then the ordered pair is:
Let be the solution of the differential equation on its maximal interval of existence containing , satisfying . Find the number of roots of the equation .
A variable plane has , , and intercepts all equal to , where and . Let be the locus of the image of the point reflected across the plane . If denotes the closure of the set , which of the following points belongs to the set ?
A point is generated in by the following random process: With probability , is chosen uniformly from the surface of the unit sphere . With probability , is chosen uniformly from the interior of the unit sphere . Let be the origin. Let be the event that the volume of the sphere centered at with radius is at least . Let be the event that lies strictly inside . Find the probability .
Consider the feasible region in the -plane determined by the following system of inequalities: Find the maximum value of the objective function over the region .
Let be the feasible region in the -plane defined by the inequalities: If denotes the greatest integer function, find the maximum value of the objective function on the region .
A factory produces three chemicals and in quantities and (in kg) respectively, where . The total production must be exactly kg. Due to safety regulations, the production state must satisfy a stability constraint: its perpendicular distance from the plane cannot exceed units. The profit per kg for chemicals and are and respectively. The profit per kg for chemical is , where is the maximum possible value of for complex numbers satisfying and . Find the maximum total profit the factory can achieve.
Let be continuous functions such that both satisfy the differential equation for all . Given that , , , and . Let be the region in the -plane defined by The area of the region is:
Let be the line tangent to the parabola that is parallel to the line . Let be the feasible region in the -plane defined by the system of inequalities: What is the area of the region ?
Let denote the fractional part of . Find the number of real solutions to the equation
Let be three vectors such that , , and . It is given that and . If the matrix is invertible, let be the set of all possible values of the dot product . Which of the following represents the exact set ?
Let be the region in the -plane defined by the system of inequalities and . Let and () be the abscissae of the intersection points of the curves and .
A function is defined as
Find the value of .
Let be the set of all integer solutions to the system of inequalities: Let be the number of elements in set . If denotes the sum of the first terms of a sequence and is given by , then the value of is:
Let be the solution set of the system of inequalities and . Let be defined by Let be the right-hand derivative of at . Let be the value of for the point guaranteed by Lagrange's Mean Value Theorem for on . If exists, find the value of . (If does not exist, select the corresponding option).
Evaluate the integral: where denotes the greatest integer less than or equal to .
Let for . Find the value of .
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