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CBSE Class 12 Mathematics 2023 question paper (65/5)

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
    Let A = {3, 5}. Then number of reflexive relations on A is

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  2. Q.21 mark
    sin⁡[π3+sin⁡−1(12)]\sin\left[\dfrac{\pi}{3} + \sin^{-1}\left(\dfrac{1}{2}\right)\right] is equal to

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  3. Q.31 mark
    If for a square matrix A, A2−A+I=OA^2 - A + I = O, then A−1A^{-1} equals

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  4. Q.41 mark
    If A=[1021]A = \begin{bmatrix} 1 & 0 \\ 2 & 1 \end{bmatrix}, B=[x011]B = \begin{bmatrix} x & 0 \\ 1 & 1 \end{bmatrix} and A=B2A = B^2, then xx equals

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  5. Q.51 mark
    If ∣α34121141∣=0\begin{vmatrix} \alpha & 3 & 4 \\ 1 & 2 & 1 \\ 1 & 4 & 1 \end{vmatrix} = 0, then the value of α\alpha is

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  6. Q.61 mark
    The derivative of x2xx^{2x} w.r.t. xx is

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  7. Q.71 mark
    The function f(x)=[x]f(x) = [x], where [x][x] denotes the greatest integer less than or equal to xx, is continuous at

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  8. Q.81 mark
    If x=Acos⁡4t+Bsin⁡4tx = A\cos 4t + B\sin 4t, then d2xdt2\dfrac{d^2x}{dt^2} is equal to

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  9. Q.91 mark
    The interval in which the function f(x)=2x3+9x2+12x−1f(x) = 2x^3 + 9x^2 + 12x - 1 is decreasing, is

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  10. Q.101 mark
    ∫sec⁡xsec⁡x−tan⁡x dx\displaystyle\int \dfrac{\sec x}{\sec x - \tan x}\,dx equals

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  11. Q.111 mark
    ∫−11∣x−2∣x−2 dx\displaystyle\int_{-1}^{1} \dfrac{|x - 2|}{x - 2}\,dx, x≠2x \ne 2 is equal to

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  12. Q.121 mark
    The sum of the order and the degree of the differential equation ddx((dydx)3)\dfrac{d}{dx}\left(\left(\dfrac{dy}{dx}\right)^3\right) is

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  13. Q.131 mark
    Two vectors a⃗=a1i^+a2j^+a3k^\vec{a} = a_1\hat{i} + a_2\hat{j} + a_3\hat{k} and b⃗=b1i^+b2j^+b3k^\vec{b} = b_1\hat{i} + b_2\hat{j} + b_3\hat{k} are collinear if

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  14. Q.141 mark
    The magnitude of the vector 6i^−2j^+3k^6\hat{i} - 2\hat{j} + 3\hat{k} is

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  15. Q.151 mark
    If a line makes angles of 90∘90^{\circ}, 135∘135^{\circ} and 45∘45^{\circ} with the xx, y and z axes respectively, then its direction cosines are

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  16. Q.161 mark
    The angle between the lines 2x=3y=−z2x = 3y = -z and 6x=−y=−4z6x = -y = -4z is

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  17. Q.171 mark
    If for any two events A and B, P(A)=45P(A) = \dfrac{4}{5} and P(A∩B)=710P(A \cap B) = \dfrac{7}{10}, then P(B/A) is equal to

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  18. Q.181 mark
    Five fair coins are tossed simultaneously. The probability of the events that atleast one head comes up is

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  19. In the following questions 19 and 20, a statement of Assertion (A) is followed by a statement of Reason (R). Choose the correct answer out of the following choices :
    Q.191 mark
    Assertion (A) : Two coins are tossed simultaneously. The probability of getting two heads, if it is known that at least one head comes up, is 13\dfrac{1}{3}. Reason (R) : Let E and F be two events with a random experiment, then P(F/E)=P(E∩F)P(E)P(F/E) = \dfrac{P(E \cap F)}{P(E)}.

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  20. Q.201 mark
    Assertion (A) : ∫2810−xx+10−x dx=3\displaystyle\int_{2}^{8} \dfrac{\sqrt{10 - x}}{\sqrt{x} + \sqrt{10 - x}}\,dx = 3 Reason (R) : ∫abf(x) dx=∫abf(a+b−x) dx\displaystyle\int_{a}^{b} f(x)\,dx = \int_{a}^{b} f(a + b - x)\,dx

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Section B

2 marks each

  1. Q.212 marks
    Write the domain and range (principle value branch) of the following functions : f(x)=tan⁡−1xf(x) = \tan^{-1} x
  2. Q.22 (a)2 marks
    If f(x)={x2,if x≥1x,if x<1f(x) = \begin{cases} x^2, & \text{if } x \ge 1 \\ x, & \text{if } x < 1 \end{cases}, then show that f is not differentiable at x=1x = 1.
  3. OR

    Q.22 (b)2 marks
    Find the value(s) of 'λ\lambda', if the function f(x)={sin⁡2λxx2,if x≠01,if x=0f(x) = \begin{cases} \dfrac{\sin^2 \lambda x}{x^2}, & \text{if } x \ne 0 \\ 1, & \text{if } x = 0 \end{cases} is continuous at x=0x = 0.
  4. Q.232 marks
    Sketch the region bounded by the lines 2x+y=82x + y = 8, y=2y = 2, y=4y = 4 and the y-axis. Hence, obtain its area using integration.
  5. Q.24 (a)2 marks
    If the vectors a⃗\vec{a} and b⃗\vec{b} are such that ∣a⃗∣=3|\vec{a}| = 3, ∣b⃗∣=23|\vec{b}| = \dfrac{2}{3} and a⃗×b⃗\vec{a} \times \vec{b} is a unit vector, then find the angle between a⃗\vec{a} and b⃗\vec{b}.
  6. OR

    Q.24 (b)2 marks
    Find the area of a parallelogram whose adjacent sides are determined by the vectors a⃗=i^−j^+3k^\vec{a} = \hat{i} - \hat{j} + 3\hat{k} and b⃗=2i^−7j^+k^\vec{b} = 2\hat{i} - 7\hat{j} + \hat{k}.
  7. Q.252 marks
    Find the vector and the cartesian equations of a line that passes through the point A(1, 2, −1-1) and parallel to the line 5x−25=14−7y=35z5x - 25 = 14 - 7y = 35z.

Section C

3 marks each

  1. Q.263 marks
    If A=[1233−21421]A = \begin{bmatrix} 1 & 2 & 3 \\ 3 & -2 & 1 \\ 4 & 2 & 1 \end{bmatrix}, then show that A3−23A−40I=OA^3 - 23A - 40I = O.
  2. Q.27 (a)3 marks
    Differentiate sec⁡−1(11−x2)\sec^{-1}\left(\dfrac{1}{\sqrt{1 - x^2}}\right) w.r.t. sin⁡−1(2x1−x2)\sin^{-1}(2x\sqrt{1 - x^2}).
  3. OR

    Q.27 (b)3 marks
    If y=tan⁡x+sec⁡xy = \tan x + \sec x, then prove that d2ydx2=cos⁡x(1−sin⁡x)2\dfrac{d^2y}{dx^2} = \dfrac{\cos x}{(1 - \sin x)^2}.
  4. Q.28 (a)3 marks
    Evaluate : ∫02π11+esin⁡x dx\displaystyle\int_{0}^{2\pi} \dfrac{1}{1 + e^{\sin x}}\,dx
  5. OR

    Q.28 (b)3 marks
    Find : ∫x4(x−1)(x2+1) dx\displaystyle\int \dfrac{x^4}{(x - 1)(x^2 + 1)}\,dx
  6. Q.293 marks
    Find the area of the following region using integration : {(x,y):y2≤2x and y≥x−4}\{(x, y) : y^2 \le 2x \text{ and } y \ge x - 4\}
  7. Q.30 (a)3 marks
    Find the coordinates of the foot of the perpendicular drawn from the point P(0, 2, 3) to the line x+35=y−12=z+43\dfrac{x + 3}{5} = \dfrac{y - 1}{2} = \dfrac{z + 4}{3}.
  8. OR

    Q.30 (b)3 marks
    Three vectors a⃗\vec{a}, b⃗\vec{b} and c⃗\vec{c} satisfy the condition a⃗+b⃗+c⃗=0⃗\vec{a} + \vec{b} + \vec{c} = \vec{0}. Evaluate the quantity μ=a⃗⋅b⃗+b⃗⋅c⃗+c⃗⋅a⃗\mu = \vec{a} \cdot \vec{b} + \vec{b} \cdot \vec{c} + \vec{c} \cdot \vec{a}, if ∣a⃗∣=3|\vec{a}| = 3, ∣b⃗∣=4|\vec{b}| = 4 and ∣c⃗∣=2|\vec{c}| = 2.
  9. Q.313 marks
    Find the distance between the lines : r⃗=(i^+2j^−4k^)+λ(2i^+3j^+6k^)\vec{r} = (\hat{i} + 2\hat{j} - 4\hat{k}) + \lambda(2\hat{i} + 3\hat{j} + 6\hat{k}); r⃗=(3i^+3j^−5k^)+μ(4i^+6j^+12k^)\vec{r} = (3\hat{i} + 3\hat{j} - 5\hat{k}) + \mu(4\hat{i} + 6\hat{j} + 12\hat{k})

Section D

5 marks each

  1. Q.32 (a)5 marks
    The median of an equilateral triangle is increasing at the rate of 232\sqrt{3} cm/s. Find the rate at which its side is increasing.
  2. OR

    Q.32 (b)5 marks
    Sum of two numbers is 5. If the sum of the cubes of these numbers is least, then find the sum of the squares of these numbers.
  3. Q.335 marks
    Evaluate : ∫0π/2sin⁡2xtan⁡−1(sin⁡x) dx\displaystyle\int_{0}^{\pi/2} \sin 2x \tan^{-1}(\sin x)\,dx
  4. Q.345 marks
    Solve the following Linear Programming Problem graphically : Maximize : P=70x+40yP = 70x + 40y subject to : 3x+2y≤93x + 2y \le 9, 3x+y≤93x + y \le 9, x≥0, y≥0x \ge 0,\ y \ge 0
  5. Q.35 (a)5 marks
    In answering a question on a multiple choice test, a student either knows the answer or guesses. Let 35\dfrac{3}{5} be the probability that he knows the answer and 25\dfrac{2}{5} be the probability that he guesses. Assuming that a student who guesses at the answer will be correct with probability 13\dfrac{1}{3}. What is the probability that the student knows the answer, given that he answered it correctly ?
  6. OR

    Q.35 (b)5 marks
    A box contains 10 tickets, 2 of which carry a prize of ₹ 8 each, 5 of which carry a prize of ₹ 4 each, and remaining 3 carry a prize of ₹ 2 each. If one ticket is drawn at random, find the mean value of the prize.

Section E

  1. An organization conducted bike race under two different categories – Boys and Girls. There were 28 participants in all. Among all of them, finally three from category 1 and two from category 2 were selected for the final race. Ravi forms two sets B and G with these participants for his college project. Let B = {b1,b2,b3}\{b_1, b_2, b_3\} and G = {g1,g2}\{g_1, g_2\}, where B represents the set of Boys selected and G the set of Girls selected for the final race. Based on the above information, answer the following questions :
    Q.36 (i)1 mark
    How many relations are possible from B to G ?
  2. Q.36 (ii)1 mark
    Among all the possible relations from B to G, how many functions can be formed from B to G ?
  3. Q.36 (iii) (a)2 marks
    Let R:B→BR : B \to B be defined by R={(x,y):x and y are students of the same sex}R = \{(x, y) : x \text{ and } y \text{ are students of the same sex}\}. Check if R is an equivalence relation.
  4. OR

    Q.36 (iii) (b)2 marks
    A function f:B→Gf : B \to G be defined by f={(b1,g1),(b2,g2),(b3,g1)}f = \{(b_1, g_1), (b_2, g_2), (b_3, g_1)\}. Check if f is bijective. Justify your answer.
  5. Gautam buys 5 pens, 3 bags and 1 instrument box and pays a sum of ₹ 160. From the same shop, Vikram buys 2 pens, 1 bag and 3 instrument boxes and pays a sum of ₹ 190. Also Ankur buys 1 pen, 2 bags and 4 instrument boxes and pays a sum of ₹ 250. Based on the above information, answer the following questions :
    Q.37 (i)1 mark
    Convert the given above situation into a matrix equation of the form AX = B.
  6. Q.37 (ii)1 mark
    Find ∣A∣|A|.
  7. Q.37 (iii) (a)2 marks
    Find A−1A^{-1}.
  8. OR

    Q.37 (iii) (b)2 marks
    Determine P=A2−5AP = A^2 - 5A.
  9. An equation involving derivatives of the dependent variable with respect to the independent variables is called a differential equation. A differential equation of the form dydx=F(x,y)\dfrac{dy}{dx} = F(x, y) is said to be homogeneous if F(x, y) is a homogeneous function of degree zero, whereas a function F(x, y) is a homogenous function of degree n if F(λx,λy)=λnF(x,y)F(\lambda x, \lambda y) = \lambda^n F(x, y). To solve a homogeneous differential equation of the type dydx=F(x,y)=g(yx)\dfrac{dy}{dx} = F(x, y) = g\left(\dfrac{y}{x}\right), we make the substitution y=vxy = vx and then separate the variables. Based on the above, answer the following questions :
    Q.38 (i)2 marks
    Show that (x2−y2) dx+2xy dy=0(x^2 - y^2)\,dx + 2xy\,dy = 0 is a differential equation of the type dydx=g(yx)\dfrac{dy}{dx} = g\left(\dfrac{y}{x}\right).
  10. Q.38 (ii)2 marks
    Solve the above equation to find its general solution.