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CBSE Class 12 Mathematics 2023 question paper (65/1)

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 for a square matrix A, A2−3A+I=OA^2 - 3A + I = O and A−1=xA+yIA^{-1} = xA + yI, then the value of x + y is :

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  2. Q.21 mark
    If ∣A∣=2|A| = 2, where A is a 2×22 \times 2 matrix, then ∣4A−1∣|4A^{-1}| equals :

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  3. Q.31 mark
    Let A be a 3×33 \times 3 matrix such that ∣adj A∣=64|\text{adj } A| = 64. Then ∣A∣|A| is equal to :

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  4. Q.41 mark
    If A=[3452]A = \begin{bmatrix} 3 & 4 \\ 5 & 2 \end{bmatrix} and 2A + B is a null matrix, then B is equal to :

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  5. Q.51 mark
    If ddx(f(x))=log⁡x\frac{d}{dx}(f(x)) = \log x, then f(x) equals :

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  6. Q.61 mark
    ∫0π6sec⁡2(x−π6)dx\int\limits_{0}^{\frac{\pi}{6}} \sec^2\left(x - \frac{\pi}{6}\right) dx is equal to :

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  7. Q.71 mark
    The sum of the order and the degree of the differential equation d2ydx2+(dydx)3=sin⁡y\frac{d^2y}{dx^2} + \left(\frac{dy}{dx}\right)^3 = \sin y is :

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  8. Q.81 mark
    The value of p for which the vectors 2i^+pj^+k^2\hat{i} + p\hat{j} + \hat{k} and −4i^−6j^+26k^-4\hat{i} - 6\hat{j} + 26\hat{k} are perpendicular to each other, is :

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  9. Q.91 mark
    The value of (i^×j^)⋅j^+(j^×i^)⋅k^(\hat{i} \times \hat{j}) \cdot \hat{j} + (\hat{j} \times \hat{i}) \cdot \hat{k} is :

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  10. Q.101 mark
    If a⃗+b⃗=i^\vec{a} + \vec{b} = \hat{i} and a⃗=2i^−2j^+2k^\vec{a} = 2\hat{i} - 2\hat{j} + 2\hat{k}, then ∣b⃗∣|\vec{b}| equals :

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  11. Q.111 mark
    Direction cosines of the line x−12=1−y3=2z−112\frac{x - 1}{2} = \frac{1 - y}{3} = \frac{2z - 1}{12} are :

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  12. Q.121 mark
    If P(AB)=0⋅3P\left(\frac{A}{B}\right) = 0{\cdot}3, P(A)=0⋅4P(A) = 0{\cdot}4 and P(B)=0⋅8P(B) = 0{\cdot}8, then P(BA)P\left(\frac{B}{A}\right) is equal to :

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  13. Q.131 mark
    The value of k for which f(x)={3x+5,x≥2kx2,x<2f(x) = \begin{cases} 3x + 5, & x \ge 2 \\ kx^2, & x < 2 \end{cases} is a continuous function, is :

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  14. Q.141 mark
    If A=[01−10]A = \begin{bmatrix} 0 & 1 \\ -1 & 0 \end{bmatrix} and (3I+4A)(3I−4A)=x2I(3I + 4A)(3I - 4A) = x^2 I, then the value(s) x is/are :

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  15. Q.151 mark
    The general solution of the differential equation x dy−(1+x2) dx=dxx \, dy - (1 + x^2) \, dx = dx is :

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  16. Q.161 mark
    If f(x)=a(x−cos⁡x)f(x) = a(x - \cos x) is strictly decreasing in R\mathbb{R}, then 'a' belongs to

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  17. Q.171 mark
    The corner points of the feasible region in the graphical representation of a linear programming problem are (2, 72), (15, 20) and (40, 15). If z = 18x + 9y be the objective function, then :

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  18. Q.181 mark
    The number of corner points of the feasible region determined by the constraints x−y≥0x - y \ge 0, 2y≤x+22y \le x + 2, x≥0x \ge 0, y≥0y \ge 0 is :

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  19. Questions number 19 and 20 are Assertion and Reason 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 range of the function f(x)=2sin⁡−1x+3π2f(x) = 2 \sin^{-1} x + \frac{3\pi}{2}, where x∈[−1,1]x \in [-1, 1], is [π2,5π2]\left[\frac{\pi}{2}, \frac{5\pi}{2}\right]. Reason (R) : The range of the principal value branch of sin⁡−1(x)\sin^{-1}(x) is [0,π][0, \pi].

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  20. Q.201 mark
    Assertion (A) : Equation of a line passing through the points (1, 2, 3) and (3,−1,3)(3, -1, 3) is x−32=y+13=z−30\frac{x - 3}{2} = \frac{y + 1}{3} = \frac{z - 3}{0}. Reason (R) : Equation of a line passing through points (x1,y1,z1)(x_1, y_1, z_1), (x2,y2,z2)(x_2, y_2, z_2) is given by x−x1x2−x1=y−y1y2−y1=z−z1z2−z1\frac{x - x_1}{x_2 - x_1} = \frac{y - y_1}{y_2 - y_1} = \frac{z - z_1}{z_2 - z_1}.

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Section B

2 marks each

  1. Q.21 (a)2 marks
    A function f:A→Bf : A \to B defined as f(x)=2xf(x) = 2x is both one-one and onto. If A={1,2,3,4}A = \{1, 2, 3, 4\}, then find the set B.
  2. OR

    Q.21 (b)2 marks
    Evaluate : sin⁡−1(sin⁡3π4)+cos⁡−1(cos⁡3π4)+tan⁡−1(1)\sin^{-1}\left(\sin \frac{3\pi}{4}\right) + \cos^{-1}\left(\cos \frac{3\pi}{4}\right) + \tan^{-1}(1)
  3. Q.222 marks
    Find all the vectors of magnitude 333\sqrt{3} which are collinear to vector i^+j^+k^\hat{i} + \hat{j} + \hat{k}.
  4. Q.23 (a)2 marks
    Position vectors of the points A, B and C as shown in the figure below are a⃗\vec{a}, b⃗\vec{b} and c⃗\vec{c} respectively. If AC→=54AB→\overrightarrow{AC} = \frac{5}{4} \overrightarrow{AB}, express c⃗\vec{c} in terms of a⃗\vec{a} and b⃗\vec{b}.
  5. OR

    Q.23 (b)2 marks
    Check whether the lines given by equations x=2λ+2x = 2\lambda + 2, y=7λ+1y = 7\lambda + 1, z=−3λ−3z = -3\lambda - 3 and x=−μ−2x = -\mu - 2, y=2μ+8y = 2\mu + 8, z=4μ+5z = 4\mu + 5 are perpendicular to each other or not.
  6. Q.242 marks
    If y=(x+x2−1)2y = \left(x + \sqrt{x^2 - 1}\right)^2, then show that (x2−1)(dydx)2=4y2(x^2 - 1)\left(\frac{dy}{dx}\right)^2 = 4y^2.
  7. Q.252 marks
    Show that the function f(x)=16sin⁡x4+cos⁡x−xf(x) = \frac{16 \sin x}{4 + \cos x} - x, is strictly decreasing in (π2,π)\left(\frac{\pi}{2}, \pi\right).

Section C

3 marks each

  1. Q.263 marks
    Evaluate : ∫0π2[log⁡(sin⁡x)−log⁡(2cos⁡x)] dx\int\limits_{0}^{\frac{\pi}{2}} [\log (\sin x) - \log (2 \cos x)] \, dx.
  2. Q.273 marks
    Find : ∫1x(x+1)(x+2) dx\int \frac{1}{\sqrt{x}\left(\sqrt{x} + 1\right)\left(\sqrt{x} + 2\right)} \, dx
  3. Q.28 (a)3 marks
    Find the particular solution of the differential equation dydx+sec⁡2x⋅y=tan⁡x⋅sec⁡2x\frac{dy}{dx} + \sec^2 x \cdot y = \tan x \cdot \sec^2 x, given that y(0) = 0.
  4. OR

    Q.28 (b)3 marks
    Solve the differential equation given by x dy−y dx−x2+y2 dx=0x \, dy - y \, dx - \sqrt{x^2 + y^2} \, dx = 0.
  5. Q.293 marks
    Solve graphically the following linear programming problem : Maximise z = 6x + 3y, subject to the constraints 4x+y≥804x + y \ge 80, 3x+2y≤1503x + 2y \le 150, x+5y≥115x + 5y \ge 115, x≥0,y≥0x \ge 0, y \ge 0.
  6. Q.30 (a)3 marks
    The probability distribution of a random variable X is given below :
    X123
    P(X)k2\frac{k}{2}k3\frac{k}{3}k6\frac{k}{6}
    (i) Find the value of k. (ii) Find P(1≤X<3)P(1 \le X < 3). (iii) Find E(X), the mean of X.
  7. OR

    Q.30 (b)3 marks
    A and B are independent events such that P(A∩B‾)=14P(A \cap \overline{B}) = \frac{1}{4} and P(A‾∩B)=16P(\overline{A} \cap B) = \frac{1}{6}. Find P(A) and P(B).
  8. Q.31 (a)3 marks
    Evaluate : ∫0π2exsin⁡x dx\int\limits_{0}^{\frac{\pi}{2}} e^x \sin x \, dx
  9. OR

    Q.31 (b)3 marks
    Find : ∫1cos⁡(x−a) cos⁡(x−b) dx\int \frac{1}{\cos(x - a) \, \cos(x - b)} \, dx

Section D

5 marks each

  1. Q.325 marks
    A relation R is defined on a set of real numbers R\mathbb{R} as R={(x,y):x⋅y is an irrational number}R = \{(x, y) : x \cdot y \text{ is an irrational number}\}. Check whether R is reflexive, symmetric and transitive or not.
  2. Q.33 (a)5 marks
    If A=[12−2−1300−21]A = \begin{bmatrix} 1 & 2 & -2 \\ -1 & 3 & 0 \\ 0 & -2 & 1 \end{bmatrix} and B−1=[3−11−156−55−22]B^{-1} = \begin{bmatrix} 3 & -1 & 1 \\ -15 & 6 & -5 \\ 5 & -2 & 2 \end{bmatrix}, find (AB)−1(AB)^{-1}.
  3. OR

    Q.33 (b)5 marks
    Solve the following system of equations by matrix method : x+2y+3z=6x + 2y + 3z = 6 2x−y+z=22x - y + z = 2 3x+2y−2z=33x + 2y - 2z = 3
  4. Q.34 (a)5 marks
    Find the vector and the Cartesian equations of a line passing through the point (1,2,−4)(1, 2, -4) and parallel to the line joining the points A(3,3,−5)A(3, 3, -5) and B(1,0,−11)B(1, 0, -11). Hence, find the distance between the two lines.
  5. OR

    Q.34 (b)5 marks
    Find the equations of the line passing through the points A(1, 2, 3) and B(3, 5, 9). Hence, find the coordinates of the points on this line which are at a distance of 14 units from point B.
  6. Q.355 marks
    Find the area of the region bounded by the curves x2=yx^2 = y, y=x+2y = x + 2 and x-axis, using integration.

Section E

  1. There are different types of Yoga which involve the usage of different poses of Yoga Asanas, Meditation and Pranayam as shown in the figure below : The Venn diagram below represents the probabilities of three different types of Yoga, A, B and C performed by the people of a society. Further, it is given that probability of a member performing type C Yoga is 0⋅440{\cdot}44. On the basis of the above information, answer the following questions :
    Q.36 (i)1 mark
    Find the value of x.
  2. Q.36 (ii)1 mark
    Find the value of y.
  3. Q.36 (iii) (a)2 marks
    Find P(CB)P\left(\frac{C}{B}\right).
  4. OR

    Q.36 (iii) (b)2 marks
    Find the probability that a randomly selected person of the society does Yoga of type A or B but not C.
  5. A tank, as shown in the figure below, formed using a combination of a cylinder and a cone, offers better drainage as compared to a flat bottomed tank. A tap is connected to such a tank whose conical part is full of water. Water is dripping out from a tap at the bottom at the uniform rate of 2 cm3/s2 \text{ cm}^3/\text{s}. The semi-vertical angle of the conical tank is 45∘45^\circ. On the basis of given information, answer the following questions :
    Q.37 (i)1 mark
    Find the volume of water in the tank in terms of its radius r.
  6. Q.37 (ii)1 mark
    Find rate of change of radius at an instant when r=22r = 2\sqrt{2} cm.
  7. Q.37 (iii) (a)2 marks
    Find the rate at which the wet surface of the conical tank is decreasing at an instant when radius r=22r = 2\sqrt{2} cm.
  8. OR

    Q.37 (iii) (b)2 marks
    Find the rate of change of height 'h' at an instant when slant height is 4 cm.
  9. The equation of the path traced by a roller-coaster is given by the polynomial f(x)=a(x+9)(x+1)(x−3)f(x) = a(x + 9)(x + 1)(x - 3). If the roller-coaster crosses y-axis at a point (0,−1)(0, -1), answer the following :
    Q.38 (i)2 marks
    Find the value of 'a'.
  10. Q.38 (ii)2 marks
    Find f′′(x)f''(x) at x = 1.