CBSE 12 MATHS 2025 SET3

The principal value of sin⁻¹(sin(−10π/3)) is:

If A and B are square matrices of same order such that AB = A and BA = B, then A² + B² is equal to:

For real x, let f(x) = x³ + 5x + 1. Then:

If y = sin⁻¹x, then (d²y/dx²)(1 − x²) is equal to:

The value of λ so that f(x) = sinx − cosx − λx + C decreases for all real values of x are:

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:

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

If f(x) = { 3x − 2, 0 ≤ x ≤ 1 ; 2x² + ax, 1 < x < 2 } is continuous for x ∈ (0, 2), then a is equal to:

If f : N → W is defined as f(n) = { n/2, if n is even ; 0, if n is odd }, then f is:

The matrix [[0, −1, 2], [1, 0, 7], [−2, −7, 0]] is a:

If the sides AB and AC of △ABC are represented by vectors ĵ + k̂ and 3î − ĵ + 4k̂ respectively, then the length of the median through A on BC is:

The function f defined by f(x) = { x, if x ≤ 1 ; 5, if x > 1 } is not continuous at:

If f(x) = 2x + cosx, then f(x):

∫(cos2x − cos2α)/(cosx − cosα) dx is equal to:

The value of ∫₀¹ dx/(eˣ + e⁻ˣ) is:

The order and degree of the differential equation d²y/dx² + (dy/dx)² = xsin(dy/dx) are:

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

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:

Assertion: If A and B are two events such that P(A ∩ B) = 0, then A and B are independent events. Reason: Two events are independent if the occurrence of one does not affect the occurrence of the other.

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

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).

(a) Find the least value of 'a' so that f(x) = 2x² − ax + 3 is an increasing function on [2, 4]. OR (b) If f(x) = x + 1/x, x > 1, show that f is an increasing function.

(a) Simplify sin⁻¹(x/√(1+x²)). OR (b) Find the domain of sin⁻¹(x − 1).

Calculate the area of the region bounded by the curve x²/9 + y²/4 = 1 and the x-axis using integration.

For the curve y = 5x − 2x³, if x increases at the rate of 2 units/s, then how fast is the slope of the curve changing when x = 2?

(a) If f: R⁺ → R is defined as f(x) = log_a x (a > 0 and a ≠ 1), prove that f is a bijection. (R⁺ is set of all positive real numbers.) OR (b) Let A = {1, 2, 3} and B = {4, 5, 6}. A relation R from A to B is defined as R = {(x, y): x + y = 6, x ∈ A, y ∈ B}. (i) Write all elements of R. (ii) Is R a function? Justify. (iii) Determine domain and range of R.

(a) Find k so that f(x) = { (x² – 2x – 3)/(x + 1), x ≠ –1 ; k, x = –1 } is continuous at x = –1. OR (b) Check the differentiability of function f(x) = x|x| at x = 0.

Evaluate: ∫ eˣ · (1 – sin x) / (1 – cos x) dx

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

Find the distance of the point (–1, –5, –10) from the point of intersection of the lines (x–1)/2 = (y–2)/3 = (z–3)/4 and (x–4)/5 = (y–1)/2 = z.

Solve the following Linear Programming Problem using graphical method: Maximise Z = 100x + 50y subject to the constraints: 3x + y ≤ 600 x + y ≤ 300 y ≤ x + 200 x ≥ 0, y ≥ 0

If A is a 3 × 3 invertible matrix, show that for any scalar k ≠ 0, (kA)⁻¹ = (1/k) A⁻¹. Hence calculate (3A)⁻¹, where A = [[2, –1, 1], [–1, 2, –1], [1, –1, 2]].

The relation between the height of the plant (y cm) with respect to exposure to sunlight is governed by the equation y = 4x – (1/2)x², where x is the number of days exposed to sunlight. (i) Find the rate of growth of the plant with respect to sunlight. (ii) In how many days will the plant attain its maximum height? What is the maximum height?

(a) Find: ∫ cos x / ((4 + sin²x)(5 – 4cos²x)) dx OR (b) Evaluate: ∫₀^π dx / (a²cos²x + b²sin²x)

(a) Show that the area of a parallelogram whose diagonals are represented by vectors a and b is given by (1/2)|a × b|. Also find the area of a parallelogram whose diagonals are 2î – ĵ + k̂ and î + 3ĵ – k̂. OR (b) 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 (x–8)/3 = (y+19)/–16 = (z–10)/7, and r = (15î + 29ĵ + 5k̂) + λ(3î + 8ĵ – 5k̂).

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: Ajay – 47.7 m; Bijoy – 47.07 m; Kartik – 43.09 m; Dinesh – 43.9 m; Devesh – 45.2 m. The students were asked to identify who has thrown the javelin the farthest. The teacher concludes that 40% of the students have the misconception in the concept of decimal comparison and the rest do not. 80% of the students having misconception answered Bijoy as the correct answer. 90% of the students 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? (ii) What is the probability that a randomly selected student answers Bijoy as his answer in the test? (iii) (a) What is the probability that a student who answered as Bijoy is having misconception? OR (iii) (b) What is the probability that a student who answered as Bijoy is amongst students who do not have the misconception?

The students were asked to identify who has thrown the javelin the farthest. The distances thrown by students are: Ajay 47.7m, Bijoy 47.07m, Kartik 43.09m, Dinesh 43.9m, Devesh 45.2m. 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. (i) What is the probability of a student not having misconception but still answers Bijoy in the test? (ii) What is the probability that a randomly selected student answers Bijoy as his answer in the test? (iii) (a) What is the probability that a student who answered as Bijoy is having misconception? OR (iii) (b) What is the probability that a student who answered as Bijoy is amongst students who do not have the misconception?

An engineer is designing a new metro rail network in a city. (i) Find whether the two metro tracks are parallel. (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 (l1) and pass through the point (1, -2, -3). (iii) (a) 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. OR (iii) (b) Find the shortest distance between Line A and Line B.

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 (25°C). Initially the processor's temperature is 85°C. The rate of cooling is defined by the equation d/dt(T(t)) = -k(T(t) - 25), where T(t) represents the temperature of the processor at time t (in minutes) and k is a constant. (i) Find the expression for temperature of processor, T(t) given that T(0) = 85°C. (ii) How long will it take for the processor's temperature to reach 40°C? Given that k = 0.03 and loge 4 = 1.3863.