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CBSE Class 12 Mathematics 2024 question paper (65/4)

Maximum marks 80 · Time 3 hours · 3 sets

Try each question first, then open its model answer. Where the paper offers a choice, both questions are shown with OR between them.

Section A

1 mark each

  1. Q.11 mark
    If [ac0bd0005]\begin{bmatrix} a & c & 0 \\ b & d & 0 \\ 0 & 0 & 5 \end{bmatrix} is a scalar matrix, then the value of a+2b+3c+4da + 2b + 3c + 4d is :

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  2. Q.21 mark
    Given that A−1=17[21−32]A^{-1} = \dfrac{1}{7}\begin{bmatrix} 2 & 1 \\ -3 & 2 \end{bmatrix}, matrix A is :

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  3. Q.31 mark
    If A=[21−4−2]A = \begin{bmatrix} 2 & 1 \\ -4 & -2 \end{bmatrix}, then the value of I−A+A2−A3+…I - A + A^2 - A^3 + \ldots is :

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  4. Q.41 mark
    If A=[−20012351−1]A = \begin{bmatrix} -2 & 0 & 0 \\ 1 & 2 & 3 \\ 5 & 1 & -1 \end{bmatrix}, then the value of ∣ A (adj. A) ∣|\,A\,(\text{adj. }A)\,| is :

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  5. Q.51 mark
    Given that [1x][40−20]=0[1 \quad x]\begin{bmatrix} 4 & 0 \\ -2 & 0 \end{bmatrix} = 0, the value of xx is :

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  6. Q.61 mark
    Derivative of e2xe^{2x} with respect to exe^{x}, is :

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  7. Q.71 mark
    For what value of k, the function given below is continuous at x=0x = 0 ? f(x)={4+x−2x,x≠0k,x=0f(x) = \begin{cases} \dfrac{\sqrt{4+x} - 2}{x}, & x \neq 0 \\ k, & x = 0 \end{cases}

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  8. Q.81 mark
    The value of ∫03dx9−x2\displaystyle\int_{0}^{3} \dfrac{dx}{\sqrt{9 - x^2}} is :

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  9. Q.91 mark
    The general solution of the differential equation x dy+y dx=0x\,dy + y\,dx = 0 is :

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  10. Q.101 mark
    The integrating factor of the differential equation (x+2y2)dydx=y (y>0)(x + 2y^2)\dfrac{dy}{dx} = y\ (y > 0) is :

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  11. Q.111 mark
    If a⃗\vec{a} and b⃗\vec{b} are two vectors such that ∣a⃗∣=1|\vec{a}| = 1, ∣b⃗∣=2|\vec{b}| = 2 and a⃗⋅b⃗=3\vec{a} \cdot \vec{b} = \sqrt{3}, then the angle between 2a⃗2\vec{a} and −b⃗-\vec{b} is :

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  12. Q.121 mark
    The vectors a⃗=2i^−j^+k^\vec{a} = 2\hat{i} - \hat{j} + \hat{k}, b⃗=i^−3j^−5k^\vec{b} = \hat{i} - 3\hat{j} - 5\hat{k} and c⃗=−3i^+4j^+4k^\vec{c} = -3\hat{i} + 4\hat{j} + 4\hat{k} represents the sides of

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  13. Q.131 mark
    Let a⃗\vec{a} be any vector such that ∣a⃗∣=a|\vec{a}| = a. The value of ∣a⃗×i^∣2+∣a⃗×j^∣2+∣a⃗×k^∣2|\vec{a} \times \hat{i}|^{2} + |\vec{a} \times \hat{j}|^{2} + |\vec{a} \times \hat{k}|^{2} is :

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  14. Q.141 mark
    The vector equation of a line passing through the point (1,−1,0)(1, -1, 0) and parallel to Y-axis is :

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  15. Q.151 mark
    The lines 1−x2=y−13=z1\dfrac{1-x}{2} = \dfrac{y-1}{3} = \dfrac{z}{1} and 2x−32p=y−1=z−47\dfrac{2x-3}{2p} = \dfrac{y}{-1} = \dfrac{z-4}{7} are perpendicular to each other for p equal to :

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  16. Q.161 mark
    The maximum value of Z=4x+yZ = 4x + y for a L.P.P. whose feasible region is given below is :

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  17. Q.171 mark
    The probability distribution of a random variable X is :
    X01234
    P(X)0.1k2kk0.1
    where k is some unknown constant. The probability that the random variable X takes the value 2 is :

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  18. Q.181 mark
    The function f(x)=kx−sin⁡xf(x) = kx - \sin x is strictly increasing for

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  19. Questions No. 19 & 20, are Assertion (A) and Reason (R) based questions carrying 1 mark each. Two statements are given, one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer from the codes (A), (B), (C) and (D) as given below :
    Q.191 mark
    Assertion (A) : The relation R={(x,y):(x+y)R = \{(x, y) : (x + y) is a prime number and x,y∈N}x, y \in N\} is not a reflexive relation. Reason (R) : The number '2n' is composite for all natural numbers n.

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  20. Q.201 mark
    Assertion (A) : The corner points of the bounded feasible region of a L.P.P. are shown below. The maximum value of Z=x+2yZ = x + 2y occurs at infinite points. Reason (R) : The optimal solution of a LPP having bounded feasible region must occur at corner points.

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Section B

2 marks each

  1. Q.21 (a)2 marks
    Express tan⁡−1(cos⁡x1−sin⁡x)\tan^{-1}\left(\dfrac{\cos x}{1 - \sin x}\right), where −π2<x<π2\dfrac{-\pi}{2} < x < \dfrac{\pi}{2} in the simplest form.
  2. OR

    Q.21 (b)2 marks
    Find the principal value of tan⁡−1(1)+cos⁡−1(−12)+sin⁡−1(−12)\tan^{-1}(1) + \cos^{-1}\left(-\dfrac{1}{2}\right) + \sin^{-1}\left(-\dfrac{1}{\sqrt{2}}\right).
  3. Q.22 (a)2 marks
    If y=cos⁡3(sec⁡22t)y = \cos^{3}(\sec^{2} 2t), find dydt\dfrac{dy}{dt}.
  4. OR

    Q.22 (b)2 marks
    If xy=ex−yx^{y} = e^{x-y}, prove that dydx=log⁡x(1+log⁡x)2\dfrac{dy}{dx} = \dfrac{\log x}{(1 + \log x)^{2}}.
  5. Q.232 marks
    Find the interval in which the function f(x)=x4−4x3+10f(x) = x^{4} - 4x^{3} + 10 is strictly decreasing.
  6. Q.242 marks
    The volume of a cube is increasing at the rate of 6 cm3^{3}/s. How fast is the surface area of cube increasing, when the length of an edge is 8 cm ?
  7. Q.252 marks
    Find : ∫1x(x2−1) dx\displaystyle\int \dfrac{1}{x(x^{2} - 1)}\,dx.

Section C

3 marks each

  1. Q.263 marks
    Given that y=(sin⁡x)x⋅xsin⁡x+axy = (\sin x)^{x} \cdot x^{\sin x} + a^{x}, find dydx\dfrac{dy}{dx}.
  2. Q.27 (a)3 marks
    Evaluate : ∫0π/4x dx1+cos⁡2x+sin⁡2x\displaystyle\int_{0}^{\pi/4} \dfrac{x\,dx}{1 + \cos 2x + \sin 2x}
  3. OR

    Q.27 (b)3 marks
    Find : ∫ex[1(1+x2)3/2+x1+x2]dx\displaystyle\int e^{x}\left[\dfrac{1}{(1 + x^{2})^{3/2}} + \dfrac{x}{\sqrt{1 + x^{2}}}\right] dx
  4. Q.283 marks
    Find : ∫3x+5x2+2x+4 dx\displaystyle\int \dfrac{3x + 5}{\sqrt{x^{2} + 2x + 4}}\,dx
  5. Q.29 (a)3 marks
    Find the particular solution of the differential equation dydx=ycot⁡2x\dfrac{dy}{dx} = y \cot 2x, given that y(π4)=2y\left(\dfrac{\pi}{4}\right) = 2.
  6. OR

    Q.29 (b)3 marks
    Find the particular solution of the differential equation (xey/x+y)dx=x dy\left(xe^{y/x} + y\right) dx = x\,dy, given that y=1y = 1 when x=1x = 1.
  7. Q.303 marks
    Solve the following linear programming problem graphically : Maximise Z=2x+3yZ = 2x + 3y subject to the constraints : x+y≤6x + y \le 6 x≥2x \ge 2 y≤3y \le 3 x,y≥0x, y \ge 0
  8. Q.31 (a)3 marks
    A card from a well shuffled deck of 52 playing cards is lost. From the remaining cards of the pack, a card is drawn at random and is found to be a King. Find the probability of the lost card being a King.
  9. OR

    Q.31 (b)3 marks
    A biased die is twice as likely to show an even number as an odd number. If such a die is thrown twice, find the probability distribution of the number of sixes. Also, find the mean of the distribution.

Section D

5 marks each

  1. Q.32 (a)5 marks
    Sketch the graph of y=x ∣x∣y = x\,|x| and hence find the area bounded by this curve, X-axis and the ordinates x=−2x = -2 and x=2x = 2, using integration.
  2. OR

    Q.32 (b)5 marks
    Using integration, find the area bounded by the ellipse 9x2+25y2=2259x^{2} + 25y^{2} = 225, the lines x=−2x = -2, x=2x = 2, and the X-axis.
  3. Q.33 (a)5 marks
    Let A=R−{5}A = R - \{5\} and B=R−{1}B = R - \{1\}. Consider the function f:A→Bf : A \to B, defined by f(x)=x−3x−5f(x) = \dfrac{x-3}{x-5}. Show that f is one-one and onto.
  4. OR

    Q.33 (b)5 marks
    Check whether the relation S in the set of real numbers R defined by S={(a,b):where a−b+2 is an irrational number}S = \{(a, b) : \text{where } a - b + \sqrt{2} \text{ is an irrational number}\} is reflexive, symmetric or transitive.
  5. Q.345 marks
    If A=[21−332112−1]A = \begin{bmatrix} 2 & 1 & -3 \\ 3 & 2 & 1 \\ 1 & 2 & -1 \end{bmatrix}, find A−1A^{-1} and hence solve the following system of equations : 2x+y−3z=132x + y - 3z = 13 3x+2y+z=43x + 2y + z = 4 x+2y−z=8x + 2y - z = 8
  6. Q.35 (a)5 marks
    Find the distance between the line x2=2y−64=1−z−1\dfrac{x}{2} = \dfrac{2y-6}{4} = \dfrac{1-z}{-1} and another line parallel to it passing through the point (4,0,−5)(4, 0, -5).
  7. OR

    Q.35 (b)5 marks
    If the lines x−1−3=y−22k=z−32\dfrac{x-1}{-3} = \dfrac{y-2}{2k} = \dfrac{z-3}{2} and x−13k=y−11=z−6−7\dfrac{x-1}{3k} = \dfrac{y-1}{1} = \dfrac{z-6}{-7} are perpendicular to each other, find the value of k and hence write the vector equation of a line perpendicular to these two lines and passing through the point (3,−4,7)(3, -4, 7).

Section E

  1. A store has been selling calculators at ₹ 350 each. A market survey indicates that a reduction in price (p) of calculator increases the number of units (xx) sold. The relation between the price and quantity sold is given by the demand function p=450−12xp = 450 - \dfrac{1}{2}x. Based on the above information, answer the following questions :
    Q.36 (i)2 marks
    Determine the number of units (xx) that should be sold to maximise the revenue R(x)=x p(x)R(x) = x\,p(x). Also, verify the result.
  2. Q.36 (ii)2 marks
    What rebate in price of calculator should the store give to maximise the revenue ?
  3. An instructor at the astronomical centre shows three among the brightest stars in a particular constellation. Assume that the telescope is located at O(0, 0, 0) and the three stars have their locations at the points D, A and V having position vectors 2i^+3j^+4k^2\hat{i} + 3\hat{j} + 4\hat{k}, 7i^+5j^+8k^7\hat{i} + 5\hat{j} + 8\hat{k} and −3i^+7j^+11k^-3\hat{i} + 7\hat{j} + 11\hat{k} respectively. Based on the above information, answer the following questions :
    Q.37 (i)1 mark
    How far is the star V from star A ?
  4. Q.37 (ii)1 mark
    Find a unit vector in the direction of DA→\overrightarrow{DA}.
  5. Q.37 (iii) (a)2 marks
    Find the measure of ∠VDA\angle VDA.
  6. OR

    Q.37 (iii) (b)2 marks
    What is the projection of vector DV→\overrightarrow{DV} on vector DA→\overrightarrow{DA} ?
  7. Rohit, Jaspreet and Alia appeared for an interview for three vacancies in the same post. The probability of Rohit's selection is 15\dfrac{1}{5}, Jaspreet's selection is 13\dfrac{1}{3} and Alia's selection is 14\dfrac{1}{4}. The event of selection is independent of each other. Based on the above information, answer the following questions :
    Q.38 (i)1 mark
    What is the probability that at least one of them is selected ?
  8. Q.38 (ii)1 mark
    Find P(G ∣ H‾)P(G\,|\,\overline{H}) where G is the event of Jaspreet's selection and H‾\overline{H} denotes the event that Rohit is not selected.
  9. Q.38 (iii) (a)2 marks
    Find the probability that exactly one of them is selected.
  10. OR

    Q.38 (iii) (b)2 marks
    Find the probability that exactly two of them are selected.