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Mathematics is a crucial subject in CBSE Class 12, forming the foundation for higher education and careers in engineering, finance, data science, and research. Excelling in the subject requires conceptual clarity, strategic problem-solving, and consistent practice.
The CBSE Important Questions for Class 12 Mathematics help students focus on frequently asked, high-scoring questions from each chapter. These questions are carefully curated to align with the latest CBSE exam pattern, ensuring thorough preparation.
Below, we have provided the links to downloadable PDFs of chapter-wise important questions for class 12 Mathematics and those for different categories of marks.
Question 1: If f(x) = 3x + 2, find f⁻¹(x) and verify that f(f⁻¹(x)) = f⁻¹(f(x)) = x.
Answer: Let y = f(x) = 3x + 2. To find the inverse, we interchange x and y and solve for y.
x = 3y + 2 ⇒ y = (x - 2)/3.
Therefore, f⁻¹(x) = (x - 2)/3.
Now verify:
f(f⁻¹(x)) = 3((x - 2)/3) + 2 = (x - 2) + 2 = x.
Also, f⁻¹(f(x)) = ((3x + 2) - 2)/3 = 3x/3 = x.
Hence verified.
Question 2: Simplify sin⁻¹(cos x) for x in [0, π/2].
Answer: We know cos x = sin(π/2 - x).
So sin⁻¹(cos x) = sin⁻¹(sin(π/2 - x)) = π/2 - x.
Therefore, sin⁻¹(cos x) = π/2 - x when x ∈ [0, π/2].
Question 3: If A = [[2, 3], [1, 4]] and B = [[1, 2], [3, 1]], find AB - BA.
Answer: First, multiply A and B.
AB = [[(2)(1)+(3)(3), (2)(2)+(3)(1)], [(1)(1)+(4)(3), (1)(2)+(4)(1)]].
AB = [[2+9, 4+3], [1+12, 2+4]] = [[11, 7], [13, 6]].
Now find BA.
BA = [[(1)(2)+(2)(1), (1)(3)+(2)(4)], [(3)(2)+(1)(1), (3)(3)+(1)(4)]].
BA = [[2+2, 3+8], [6+1, 9+4]] = [[4, 11], [7, 13]].
Now AB - BA = [[11-4, 7-11], [13-7, 6-13]] = [[7, -4], [6, -7]].
Question 4: Evaluate the determinant
|3 2 1|
|2 3 1|
|1 2 3|.
Answer: Expand along the first row.
= 3(3×3 - 1×2) - 2(2×3 - 1×1) + 1(2×2 - 3×1).
= 3(9 - 2) - 2(6 - 1) + (4 - 3).
= 3×7 - 2×5 + 1 = 21 - 10 + 1 = 12.
Question 5: If f(x) = x³ and g(x) = √x, find (f ∘ g)(x) and (g ∘ f)(x).
Answer: (f ∘ g)(x) = f(g(x)) = f(√x) = (√x)³ = x^(3/2).
(g ∘ f)(x) = g(f(x)) = g(x³) = √(x³) = x^(3/2).
Hence both compositions are equal and give x^(3/2).
Question 6 : Prove that the function f(x) = x² is continuous everywhere but not differentiable at x = 0.
Answer: For continuity,
Left hand limit at 0 = lim(x→0⁻) x² = 0,
Right hand limit at 0 = lim(x→0⁺) x² = 0,
and f(0) = 0.
So LHL = RHL = f(0). Therefore, f(x) is continuous at 0.
For differentiability,
f'(x) = 2x.
At x = 0, left derivative = lim(h→0⁻) (0² - h²)/h = 0, right derivative = lim(h→0⁺) (h² - 0)/h = 0.
Both are equal, so actually f(x) = x² is differentiable at 0 too (so differentiable everywhere). Correction noted: f(x)=|x| would have been non-differentiable, not x².
Question 7: Find equation of the tangent to y = x² + 3x + 2 at x = 1.
Answer: Slope = dy/dx = 2x + 3.
At x = 1, slope m = 2(1) + 3 = 5.
Point on curve = (1, 1² + 3×1 + 2) = (1, 6).
Equation of tangent: y - 6 = 5(x - 1) → y = 5x + 1.
Question 8: Find ∫(3x² + 4x + 2) dx.
Answer: Integrate term by term.
∫3x² dx = x³, ∫4x dx = 2x², ∫2 dx = 2x.
So final answer = x³ + 2x² + 2x + C.
Question 9: Find the area under the curve y = x² between x = 0 and x = 2.
Answer: Area = ∫(0 to 2) x² dx = [x³/3]₀² = (8/3) - 0 = 8/3 square units.
Question 10: Solve differential equation dy/dx = x + y.
Answer: Rewrite as dy/dx - y = x.
This is a linear equation in y.
Integrating factor = e^(-∫1 dx) = e^(-x).
Multiply both sides by e^(-x):
e^(-x) dy/dx - e^(-x) y = x e^(-x).
Left side = d/dx(y e^(-x)) = x e^(-x).
Integrate both sides:
y e^(-x) = ∫x e^(-x) dx = -(x+1)e^(-x) + C.
Multiply by e^x: y = -x - 1 + C e^x.
Question 11: Find the dot product of vectors a = 2i + 3j + k and b = i + 2j + 3k.
Answer: a·b = (2)(1) + (3)(2) + (1)(3) = 2 + 6 + 3 = 11.
Question 12: Find the angle between vectors a = 3i - 2j and b = i + 2j.
Answer: a·b = 3×1 + (-2)×2 = 3 - 4 = -1.
|a| = √(3² + (-2)²) = √13, |b| = √(1² + 2²) = √5.
cosθ = (-1)/(√13 × √5) = -1/√65.
θ = cos⁻¹(-1/√65).
Question 13: Find equation of line passing through (1, 2, 3) and parallel to vector 2i - j + k.
Answer: Vector form: r = (i + 2j + 3k) + t(2i - j + k). Cartesian form: (x - 1)/2 = (y - 2)/(-1) = (z - 3)/1.
Question 14: Find the shortest distance between lines
r₁ = (i + 2j + 3k) + t(2i - j + k) and r₂ = (2i + 3j + k) + s(i + j - k).
Answer: Direction vectors are a₁ = (2, -1, 1), a₂ = (1, 1, -1).
Distance formula: D = |(b₂ - b₁)·(a₁ × a₂)| / |a₁ × a₂|.
b₁ = (1,2,3), b₂ = (2,3,1).
Compute a₁ × a₂ = determinant |i j k; 2 -1 1; 1 1 -1| = i((-1)(-1)-1×1) - j(2(-1)-1×1) + k(2×1 - (-1)×1).
= i(1-1) - j(-2-1) + k(2+1) = 0i - j(-3) + k(3) = 3j + 3k.
So |a₁ × a₂| = √(3² + 3²) = 3√2.
(b₂ - b₁) = (1,1,-2).
Dot with (3,3,0) = (1×0 + 1×3 + (-2)×3) = 3 - 6 = -3.
So D = | -3 | / 3√2 = 1/√2.
Question 15: Solve the linear programming problem to maximize Z = 3x + 5y subject to
x + 2y ≤ 10, 3x + 2y ≤ 18, x, y ≥ 0.
Answer: Draw lines x + 2y = 10 and 3x + 2y = 18.
Find intersection points.
x + 2y = 10 ⇒ y = (10 - x)/2.
3x + 2y = 18 ⇒ y = (18 - 3x)/2.
Solving both: (10 - x)/2 = (18 - 3x)/2 ⇒ 10 - x = 18 - 3x ⇒ 2x = 8 ⇒ x = 4.
Then y = (10 - 4)/2 = 3.
So vertices: (0,0), (0,5), (4,3), (6,0).
Now compute Z at these:
(0,0):0; (0,5):25; (4,3):27; (6,0):18.
Maximum Z = 27 at (4,3).
Question 16: Two cards are drawn from a deck of 52. Find the probability that both are aces.
Answer: Total ways = 52C2.
Favorable ways = 4C2 = 6.
P = 6/1326 = 1/221.
Question 17: A die is thrown twice. Find the probability that the sum is 8.
Answer: Total outcomes = 36.
Pairs giving sum 8: (2,6),(3,5),(4,4),(5,3),(6,2).
So 5 favorable outcomes.
P = 5/36.
Question 18: Find mean and variance of numbers 2, 4, 6, 8, 10.
Answer: Mean = (2+4+6+8+10)/5 = 30/5 = 6.
Deviations: (-4, -2, 0, 2, 4).
Squares: (16,4,0,4,16).
Variance = (16+4+0+4+16)/5 = 40/5 = 8.
Standard deviation = √8 = 2√2.
Question 19: Find conditional probability of drawing an ace given the card is a face card or ace.
Answer: Face cards = 12, aces = 4, total 16 favorable for condition. Probability of ace among these = 4/16 = 1/4.
Question 20: If A and B are independent events with P(A)=0.5, P(B)=0.6, find P(A ∩ B), P(A ∪ B), and P(A’ ∩ B’).
Answer: P(A ∩ B) = P(A)×P(B) = 0.5×0.6=0.3.
P(A ∪ B) = P(A)+P(B)-P(A ∩ B)=0.5+0.6-0.3=0.8.
P(A’ ∩ B’) = 1 - P(A ∪ B) = 1 - 0.8 = 0.2.
Each chapter in CBSE Class 12 Mathematics plays a vital role in board exams and competitive entrance tests. Here’s an overview of the key topics covered in each chapter:
Relations and Functions
Inverse Trigonometric Functions
Matrices
Determinants
Continuity and Differentiability
Applications of Derivatives
Integrals
Applications of Integrals
Differential Equations
Vector Algebra
Three-Dimensional Geometry
Linear Programming
Probability
Mastering these topics with strategic revision and problem-solving practice ensures strong conceptual clarity and better exam performance.
To simplify your preparation, here are five crucial questions from key topics, ensuring comprehensive understanding and problem-solving practice.
Question 1: Linear Programming
A company manufactures two products, P and Q. The profit per unit is ₹50 for P and ₹40 for Q. The total production is limited to 200 units, and Q cannot exceed 150 units.
Formulate and solve the linear programming problem to maximise profit.
Question 2: Probability
Two cards are drawn simultaneously from a well-shuffled deck of 52 cards.
Find the probability that both cards are aces.
Question 3: Functions and Inverse Functions
Let f be a strictly increasing function and g a strictly decreasing function, where the range of f and g match their respective codomains.
If (f ∘ g) is defined, will (f ∘ g) be invertible? Justify your answer.
Question 4: Relations and Functions
Prathibha Karanji is an innovative programme by the Government of Karnataka, where cultural and literary competitions are held between schools at cluster, block, district, and state levels.
One of these competitions, Yogasana, has two categories – Middle School and High School.
From a district, three middle school students and two high school students were selected for the state level, Let:
Part (i): Relations
A relation R: M → M is defined as:
R = {(x, y) | x and y belong to the same category}
Show that R is an equivalence relation.
Part (ii): Functions
A function f: M → H is defined as:
f = {(m₁, h₁), (m₂, h₂), (m₃, h₂)}
Prove that f is onto but not one-to-one.
Question 5: Trigonometric Functions and Composite Functions
Given:
If h(x) = f(x) + g(x), find h(0.1) and show your work.
Every year, certain types of questions frequently appear in the board exams, making it crucial to prioritise these. Solving class 12 math's important questions sharpens your analytical skills, helps identify patterns in exam papers, and ensures comprehensive coverage of critical topics.
Practising these CBSE Class 12 Important Questions will boost confidence, strengthen understanding, and improve problem-solving skills for the board exams.
Mastering mathematics requires a balance of conceptual clarity and practice. Here’s what to keep in mind:
1. Understand Core Concepts
2. Prioritise NCERT and Exemplars
3. Solve Past Years’ Papers
4. Attempt Higher-Order Thinking Skills (HOTS) Questions
Here are some of the benefits for better practising these important questions:
Here are a few tips that can help you perform well in the CBSE Class 12 Math exam.
Mathematics requires consistent practice, strategic revision, and a clear understanding of concepts. By focusing on Class 12 Mathematics Important Questions and solving them regularly, students can strengthen their problem-solving skills and improve their exam performance.
Q1. If f(x) = x² + 2x + 1, find f⁻¹(x).
Q2. Solve cos(sin⁻¹(x)) = 1/2 for x.
Q3. Find determinant of |1 2 3; 2 3 4; 3 4 5|.
Q4. Find equation of tangent to y = eˣ at x = 0.
Q5. Evaluate ∫(x³ + 2x² + 3x + 4) dx.
Q6. Solve differential equation dy/dx = y - x.
Q7. Find angle between vectors 2i + j and i - j.
Q8. A line passes through (2,3,1) and (1,-1,2). Find its vector equation.
Q9. A manufacturer makes products A and B with profits ₹40 and ₹30 per unit, total units ≤ 150, and B ≤ 100. Formulate LPP to maximize profit.
Q10. From 3 red, 4 blue, and 5 green balls, 3 are drawn. Find the probability that all are of different colors.