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CBSE Class 12 Maths 2025 Question Paper 65/4/1 with Solutions

All 45 questions from the CBSE Class 12 Mathematics board paper, Set 65/4/1 (2025), with answers and step-by-step solutions. Total 80 marks. Tap “Show answer & solution” under any question.

Set 65/1/1Set 65/1/2Set 65/1/3Set 65/2/1Set 65/2/2Set 65/2/3Set 65/4/1Set 65/4/2Set 65/4/3Set 65/5/1Set 65/5/2Set 65/5/3Set 65/6/1Set 65/6/2Set 65/6/3Set 65/7/1Set 65/7/2Set 65/7/3

The principal value of is :

  1. (A)
  2. (B)
  3. (C)
  4. (D)
Show answer & solution
Answer: (C)
  1. .
  2. Principal value of lies in , so it is .
Q21 markMCQMatrices

If A and B are square matrices of same order such that AB = A and BA = B, then is equal to :

  1. (A)A + B
  2. (B)BA
  3. (C)2 (A + B)
  4. (D)2BA
Show answer & solution
Answer: (A) A + B
  1. .
  2. .
  3. So .
Also asked in: 2025 65/4/2, 2025 65/4/3

For real x, let . Then :

  1. (A)f is one-one but not onto on R
  2. (B)f is onto on R but not one-one
  3. (C)f is one-one and onto on R
  4. (D)f is neither one-one nor onto on R
Show answer & solution
Answer: (C) f is one-one and onto on R
  1. for all x, so f is strictly increasing, hence one-one.
  2. f is a continuous cubic with as , so its range is R; f is onto.
Also asked in: 2025 65/4/2, 2025 65/4/3

If , then is equal to :

  1. (A)
  2. (B)
  3. (C)
  4. (D)
Show answer & solution
Answer: (A)
  1. .
  2. Differentiate: .
  3. Multiply by : .

The values of so that decreases for all real values of x are :

  1. (A)
  2. (B)
  3. (C)
  4. (D)
Show answer & solution
Answer: (C)
  1. .
  2. Need for all x, i.e. for all x.
  3. Maximum of is , so .
Also asked in: 2025 65/4/2, 2025 65/4/3

If P is a point on the line segment joining (3, 6, –1) and (6, 2, – 2) and y-coordinate of P is 4, then its z-coordinate is :

  1. (A)
  2. (B)0
  3. (C)1
  4. (D)
Show answer & solution
Answer: (A)
  1. Points on the segment: , .
  2. .
  3. z-coordinate .
Q71 markMCQDeterminants

If M and N are square matrices of order 3 such that det (M) = m and MN = mI, then det (N) is equal to :

  1. (A)– 1
  2. (B)1
  3. (C)
  4. (D)
Show answer & solution
Answer: (D)
  1. (order 3).
  2. .

If is continuous for , then a is equal to :

  1. (A)– 4
  2. (B)
  3. (C)– 2
  4. (D)– 1
Show answer & solution
Answer: (D) – 1
  1. Continuity at x = 1: and .
  2. .
Also asked in: 2025 65/4/2, 2025 65/4/3

If is defined as
,
then f is :

  1. (A)injective only
  2. (B)surjective only
  3. (C)a bijection
  4. (D)neither surjective nor injective
Show answer & solution
Answer: (B) surjective only
  1. , so f is not injective.
  2. For take any odd n; for take (even), then . So f is surjective.
Also asked in: 2025 65/4/2, 2025 65/4/3
Q101 markMCQMatrices

The matrix is a :

  1. (A)diagonal matrix
  2. (B)symmetric matrix
  3. (C)skew symmetric matrix
  4. (D)scalar matrix
Show answer & solution
Answer: (C) skew symmetric matrix
  1. Diagonal entries are 0 and : ; ; .
  2. So ; the matrix is skew symmetric.
Also asked in: 2025 65/4/2, 2025 65/4/3
Q111 markMCQVector Algebra

If the sides AB and AC of are represented by vectors and respectively, then the length of the median through A on BC is :

  1. (A) units
  2. (B) units
  3. (C) units
  4. (D) units
Show answer & solution
Answer: (C) units
  1. Median .
  2. units.
Also asked in: 2025 65/4/2, 2025 65/4/3

The function f defined by

is *not* continuous at :

  1. (A)x = 0
  2. (B)x = 1
  3. (C)x = 2
  4. (D)x = 5
Show answer & solution
Answer: (B) x = 1
  1. At x = 1: LHL = 1, RHL = 5, so the limit does not exist and f is discontinuous there.
  2. At every other point f is a polynomial or constant locally, hence continuous.
Also asked in: 2025 65/4/2, 2025 65/4/3

If , then f(x) :

  1. (A)has a maxima at
  2. (B)has a minima at
  3. (C)is an increasing function
  4. (D)is a decreasing function
Show answer & solution
Answer: (C) is an increasing function
  1. for all x.
  2. So f is increasing on R and has no maxima or minima.
Also asked in: 2025 65/4/2, 2025 65/4/3
Q141 markMCQIntegrals

is equal to :

  1. (A)
  2. (B)
  3. (C)
  4. (D)
Show answer & solution
Answer: (A)
  1. .
  2. Integrand .
  3. Integral .
Q151 markMCQIntegrals

The value of is :

  1. (A)
  2. (B)
  3. (C)
  4. (D)
Show answer & solution
Answer: (C)
  1. ; put , .
  2. .
  3. Value .
Also asked in: 2025 65/4/2, 2025 65/4/3

The order and degree of the differential equation
are :

  1. (A)order 2, degree 2
  2. (B)order 2, degree 1
  3. (C)order 2, degree not defined
  4. (D)order 1, degree not defined
Show answer & solution
Answer: (C) order 2, degree not defined
  1. Highest order derivative is , so order = 2.
  2. The term is not a polynomial in the derivatives, so degree is not defined.

The area of the region enclosed by the curve and the lines x = 0 and x = 4 and x-axis is :

  1. (A) sq. units
  2. (B) sq. units
  3. (C) sq. units
  4. (D) sq. units
Show answer & solution
Answer: (C) sq. units
  1. Area sq. units.
Also asked in: 2025 65/4/2, 2025 65/4/3
Q181 markMCQLinear Programming

The corner points of the feasible region of a Linear Programming Problem are (0, 2), (3, 0), (6, 0), (6, 8) and (0, 5). If Z = ax + by; (a, b > 0) be the objective function, and maximum value of Z is obtained at (0, 2) and (3, 0), then the relation between a and b is :

  1. (A)a = b
  2. (B)a = 3b
  3. (C)b = 6a
  4. (D)3a = 2b
Show answer & solution
Answer: (D) 3a = 2b
  1. Equal values at the two points: and .
  2. , i.e. .
Also asked in: 2025 65/4/2, 2025 65/4/3
Q191 markAssertion–ReasonProbability

Assertion (A): If A and B are two events such that , then A and B are independent events.
Reason (R): Two events are independent if the occurrence of one does not effect the occurrence of the other.

  1. (A)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
  2. (B)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
  3. (C)Assertion (A) is true, but Reason (R) is false.
  4. (D)Assertion (A) is false, but Reason (R) is true.
Show answer & solution
Answer: (D) Assertion (A) is false, but Reason (R) is true.
  1. Independence needs . If with , then , so A and B are not independent (they are mutually exclusive). A is false.
  2. R describes independence correctly, so R is true.
Also asked in: 2025 65/4/2, 2025 65/4/3
Q201 markAssertion–ReasonLinear Programming

Assertion (A): In a Linear Programming Problem, if the feasible region is empty, then the Linear Programming Problem has no solution.
Reason (R): A feasible region is defined as the region that satisfies all the constraints.

  1. (A)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
  2. (B)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
  3. (C)Assertion (A) is true, but Reason (R) is false.
  4. (D)Assertion (A) is false, but Reason (R) is true.
Show answer & solution
Answer: (A) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
  1. R is the definition of the feasible region, so R is true.
  2. If this region is empty, no point satisfies all constraints, so there is no feasible (hence no optimal) solution. A is true and follows from R.
Also asked in: 2025 65/4/2, 2025 65/4/3
Q212 marksVery Short AnswerDeterminants

Let A and B be two square matrices of order 3 such that det (A) = 3 and det (B) = – 4. Find the value of det (– 6AB).

Show answer & solution
Answer: 2592
  1. For order 3, .
  2. .
  3. .
Q222 marksVery Short AnswerApplication of Derivatives

Find the least value of ‘a’ so that is an increasing function on [2, 4].

Show answer & solution
Answer: f is increasing on [2, 4] for ; the boundary value is a = 8 (no least value exists).
  1. .
  2. For f increasing on [2, 4] we need for all .
  3. Minimum of on [2, 4] is 8, so .
  4. The condition is ; the extreme (greatest) admissible value is a = 8.
Also asked in: 2025 65/4/2, 2025 65/4/3
OR
Q22 (OR) (OR)2 marksVery Short AnswerApplication of Derivatives

If , , show that f is an increasing function.

Show answer & solution
Answer: Proved.
  1. .
  2. For , , so , with equality only at x = 1.
  3. Hence f is increasing on .
Also asked in: 2025 65/4/2, 2025 65/4/3
Q232 marksVery Short AnswerInverse Trigonometric Functions

Simplify .

Show answer & solution
Answer:
  1. Put , .
  2. .
  3. .
Also asked in: 2025 65/4/2, 2025 65/4/3
OR
Q23 (OR) (OR)2 marksVery Short AnswerInverse Trigonometric Functions

Find domain of .

Show answer & solution
Answer: [1, 2]
  1. Need for the square root and for .
  2. So .
  3. Domain = [1, 2].
Also asked in: 2025 65/4/2, 2025 65/4/3
Q242 marksVery Short AnswerApplication of Integrals

Calculate the area of the region bounded by the curve and the x-axis using integration.

Show answer & solution
Answer: sq. units
  1. Upper half of the ellipse: , .
  2. Area .
  3. sq. units.
Also asked in: 2025 65/4/2, 2025 65/4/3
Q252 marksVery Short AnswerApplication of Derivatives

For the curve , if x increases at the rate of 2 units/s, then how fast is the slope of the curve changing when x = 2 ?

Show answer & solution
Answer: The slope is decreasing at 48 units/s (rate = – 48 units/s).
  1. Slope .
  2. .
  3. At x = 2, : units/s.
Q263 marksShort AnswerRelations and Functions

If is defined as ( and ), prove that f is a bijection.
( is a set of all positive real numbers.)

Show answer & solution
Answer: Proved.
  1. One-one: .
  2. Onto: for any , take , so and .
  3. Hence f is one-one and onto, i.e. a bijection.
Also asked in: 2025 65/4/2, 2025 65/4/3
OR
Q26 (OR) (OR)3 marksShort AnswerRelations and Functions

Let A = {1, 2, 3} and B = {4, 5, 6}. A relation R from A to B is defined as .
(i) Write all elements of R.
(ii) Is R a function ? Justify.
(iii) Determine domain and range of R.

Show answer & solution
Answer: (i) R = {(1, 5), (2, 4)} (ii) No, 3 ∈ A has no image (iii) Domain = {1, 2}, Range = {4, 5}
  1. (i) x = 1 gives y = 5 ∈ B; x = 2 gives y = 4 ∈ B; x = 3 gives y = 3 ∉ B. So R = {(1, 5), (2, 4)}.
  2. (ii) R is not a function from A to B, because the element 3 of A is not related to any element of B.
  3. (iii) Domain of R = {1, 2}; range of R = {4, 5}.
Also asked in: 2025 65/4/2, 2025 65/4/3
Q273 marksShort AnswerContinuity and Differentiability

Find k so that

is continuous at x = – 1.

Show answer & solution
Answer: k = – 4
  1. For : .
  2. .
  3. Continuity at x = –1 needs .
Also asked in: 2025 65/4/3
OR
Q27 (OR) (OR)3 marksShort AnswerContinuity and Differentiability

Check the differentiability of function at x = 0.

Show answer & solution
Answer: f is differentiable at x = 0, with .
  1. .
  2. LHD .
  3. RHD .
  4. LHD = RHD = 0, so f is differentiable at x = 0 and .
Also asked in: 2025 65/4/3
Q283 marksShort AnswerIntegrals

Evaluate :

Show answer & solution
Answer:
  1. .
  2. With , , so the integrand is .
  3. .
  4. Value .
Q293 marksShort AnswerProbabilityNot in current syllabus

Find the probability distribution of the number of boys in families having three children, assuming equal probability for a boy and a girl.

Show answer & solution
Answer: X: 0, 1, 2, 3 with P(X):
  1. Let X = number of boys; X can be 0, 1, 2, 3. Each of the 8 outcomes (BBB, BBG, ...) has probability .
  2. (GGG), , , (BBB).
  3. Probabilities add to 1.
Also asked in: 2025 65/4/2
OR
Q29 (OR) (OR)3 marksShort AnswerProbabilityNot in current syllabus

A coin is tossed twice. Let X be a random variable defined as number of heads minus number of tails. Obtain the probability distribution of X and also find its mean.

Show answer & solution
Answer: X: – 2, 0, 2 with P(X): ; mean = 0
  1. Outcomes: HH gives X = 2; HT, TH give X = 0; TT gives X = –2.
  2. , , .
  3. Mean .
Also asked in: 2025 65/4/2
Q303 marksShort AnswerThree Dimensional Geometry

Find the distance of the point (–1, –5, –10) from the point of intersection of the lines and .

Show answer & solution
Answer: units
  1. General points: and .
  2. Equate z: . Equate y: , so .
  3. Check x: and . Point of intersection is (–1, –1, –1).
  4. Distance from (–1, –5, –10) units.
Also asked in: 2025 65/4/2, 2025 65/4/3
Q313 marksShort AnswerLinear Programming

Solve the following Linear Programming Problem using graphical method :
Maximise Z = 100x + 50y
subject to the constraints



Show answer & solution
Answer: Maximum Z = 22500 at x = 150, y = 150
  1. Draw the lines 3x + y = 600, x + y = 300 and y = x + 200 in the first quadrant; the feasible region is the polygon bounded by them and the axes.
  2. Corner points: O(0, 0), (200, 0), (150, 150) [from 3x + y = 600, x + y = 300], (50, 250) [from x + y = 300, y = x + 200], (0, 200).
  3. Z at these points: 0, 20000, 22500, 17500, 10000.
  4. Feasible region is bounded, so maximum Z = 22500 at (150, 150).
Q325 marksLong AnswerDeterminants

If A is a 3 × 3 invertible matrix, show that for any scalar , . Hence calculate , where
.

Show answer & solution
Answer:
  1. and similarly , so .
  2. .
  3. Cofactors: .
  4. , .
  5. .
Also asked in: 2025 65/4/2, 2025 65/4/3
Q335 marksLong AnswerApplication of Derivatives

The relation between the height of the plant (y cm) with respect to exposure to sunlight is governed by the equation , where x is the number of days exposed to sunlight.
(i) Find the rate of growth of the plant with respect to sunlight. (2)
(ii) In how many days will the plant attain its maximum height ? What is the maximum height ? (3)

Show answer & solution
Answer: (i) cm per day (ii) 4 days; maximum height 8 cm
  1. (i) Rate of growth .
  2. (ii) ; , so y is maximum at x = 4.
  3. Maximum height cm, attained in 4 days.
Also asked in: 2025 65/4/2, 2025 65/4/3
Q345 marksLong AnswerIntegrals

Find :

Show answer & solution
Answer:
  1. . Put , : .
  2. Treating : .
  3. .
  4. .
OR
Q34 (OR) (OR)5 marksLong AnswerIntegrals

Evaluate :

Show answer & solution
Answer: (for a, b > 0)
  1. Since , .
  2. Divide by : ; put , limits 0 to .
  3. .
  4. .
Q355 marksLong AnswerVector Algebra

Show that the area of a parallelogram whose diagonals are represented by and is given by . Also find the area of a parallelogram whose diagonals are and .

Show answer & solution
Answer: Proved; area sq. units
  1. Let the adjacent sides be ; then , (or ).
  2. .
  3. Area .
  4. .
  5. Magnitude , so area sq. units.
Also asked in: 2025 65/4/2, 2025 65/4/3
OR
Q35 (OR) (OR)5 marksLong AnswerThree Dimensional Geometry

Find the equation of a line in vector and cartesian form which passes through the point (1, 2, – 4) and is perpendicular to the lines , and .

Show answer & solution
Answer: ;
  1. Direction vectors: , .
  2. .
  3. Required line: .
  4. Cartesian form: .
Also asked in: 2025 65/4/2, 2025 65/4/3
Q364 marksCase StudyProbability

Some students are having a misconception while comparing decimals. For example, a student may mention that 78.56 > 78.9 as 7856 > 789. In order to assess this concept, a decimal comparison test was administered to the students of class VI through the following question : In the recently held Sports Day in the school, 5 students participated in a javelin throw competition. The distances to which they have thrown the javelin are shown below in the table :
Name of student: Ajay, Bijoy, Kartik, Dinesh, Devesh
Distance of javelin (in meters): 47.7, 47.07, 43.09, 43.9, 45.2
The students were asked to identify who has thrown the javelin the farthest.
Based on the test attempted by the students, the teacher concludes that 40% of the students have the misconception in the concept of decimal comparison and the rest do not have the misconception. 80% of the students having misconception answered Bijoy as the correct answer in the paper. 90% of the students who are identified with not having misconception, did not answer Bijoy as their answer.
On the basis of the above information, answer the following questions :
(i) What is the probability of a student not having misconception but still answers Bijoy in the test ? (1)
(ii) What is the probability that a randomly selected student answers Bijoy as his answer in the test ? (1)
(iii) What is the probability that a student who answered as Bijoy is having misconception ? (2)
OR (iii) What is the probability that a student who answered as Bijoy is amongst students who do not have the misconception ? (2)

Show answer & solution
Answer: (i) 0.06 (ii) 0.38 (iii) ; OR
  1. Let M: has misconception, N: no misconception, B: answers Bijoy. P(M) = 0.4, P(N) = 0.6, P(B|M) = 0.8, P(B|N) = 1 – 0.9 = 0.1.
  2. (i) .
  3. (ii) .
  4. (iii) .
  5. OR (iii) .
Also asked in: 2025 65/4/2, 2025 65/4/3
Q374 marksCase StudyThree Dimensional Geometry

An engineer is designing a new metro rail network in a city.
Initially, two metro lines, Line A and Line B, each consisting of multiple stations are designed. The track for Line A is represented by , while the track for Line B is represented by .
Based on the above information, answer the following questions :
(i) Find whether the two metro tracks are parallel. (1)
(ii) Solar panels are to be installed on the rooftop of the metro stations. Determine the equation of the line representing the placement of solar panels on the rooftop of Line A’s stations, given that panels are to be positioned parallel to Line A’s track () and pass through the point (1, – 2, – 3). (1)
(iii) To connect the stations, a pedestrian pathway perpendicular to the two metro lines is to be constructed which passes through point (3, 2, 1). Determine the equation of the pedestrian walkway. (2)
OR (iii) Find the shortest distance between Line A and Line B. (2)

Show answer & solution
Answer: (i) Not parallel (ii) (iii) ; OR units
  1. (i) Direction ratios 3, –2, 4 and 2, 1, –3 are not proportional (), so the tracks are not parallel.
  2. (ii) Line through (1, –2, –3) with direction 3, –2, 4: .
  3. (iii) .
  4. Walkway: .
  5. OR (iii) .
  6. SD units.
Also asked in: 2025 65/4/2, 2025 65/4/3
Q384 marksCase StudyDifferential Equations

During a heavy gaming session, the temperature of a student’s laptop processor increases significantly. After the session, the processor begins to cool down, and the rate of cooling is proportional to the difference between the processor’s temperature and the room temperature (C). Initially the processor’s temperature is C. The rate of cooling is defined by the equation ,
where T(t) represents the temperature of the processor at time t (in minutes) and k is a constant.
Based on the above information, answer the following questions :
(i) Find the expression for temperature of processor, T(t) given that C. (2)
(ii) How long will it take for the processor’s temperature to reach C ? Given that k = 0.03, . (2)

Show answer & solution
Answer: (i) (ii) about 46.21 minutes
  1. (i) .
  2. ; . So .
  3. (ii) .
  4. minutes (approx.).
Also asked in: 2025 65/4/2, 2025 65/4/3
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