# CBSE Class 12 Maths 2021 Answer Key

CBSE Class 12 Maths: Today the Board category twelve arithmetic test for Term-1 was conducted on 06th Dec 2021 and lakhs of twelfth category students have appeared within the testbecause the test is over currently, students should be dashing to understand the right responses to the Maths MCQ queries asked in today’s testwe have a tendency to area unit providing the solution Key of the category twelve Maths test ready by our knowledgeable college here so the scholars will match their responses tried within the test. With the right answers that area unit provided here, you’ll be able to calculate what number marks will be expected in your term-1 board test.

## CBSE Maths Class 12 Answer Key 2021 Question Paper with Answer Key

The students WHO appeared within the Maths category twelve MCQ examination will currently check their Answer Key for sophistication twelve Maths Paper that is provided here by our knowledgeable school

Q2. The number of all possible matrices of order 2 x 3 with each entry 1 or 2 is

(a) 16

(b) 6

(c) 64

(d) 24

Q3. A function f: R → R is defined as f(x) = x³ + 1. Then the function has

(a) no minimum value

(b) no maximum value

(c) both maximum and minimum values

(d) neither maximum value nor minimum value

Q4. If sin y = xcos (a +y), then dx/dy is

(a) cos a/cos² (a+y)

(b) – cos a/cos² (a+y)

(c) cos a/sin² y

(d) – cos a/sin² y

Q5. The points on the curve x²/9 + y²/25 + 1, where tangent is parallel to x-axis are

(a) (±5, 0)

(b) (0, ±5)

(c) (0, ±3)

(d) (±3, 0)

Q6. Three points P(2x, x + 3), Q(0, x) and R(x + 3, x + 6) are collinear, then x is equal to

(a) 0

(b) 2

(c) 3

(d) 1

Q7. The principal value of cos^-1 (1/2) + sin^-3 (-1/√2) is

(a) 𝞹/12

(b) 𝞹

(c) 𝞹/3

(d) 𝞹/6

Q8. If (x²+ y²)² = xy, then dy/dx is

(a) y + 4x (x²+ y²)/4y (x²+ y²) – x

(b) y – 4x (x²+ y²)/x + 4(x²+ y²) – x

(c) y – 4x (x²+ y²)/4y (x²+ y²) – x

(d) 4y(x²+ y²)- x/y-4x (x²+ y²)

Q9. If a matrix A is both symmetric and skew-symmetric, then A is necessarily

(a) Diagonal matrix

(b) Zero square matrix

(c) Square matrix

(d) Identity matrix

Q10. Let set X = {1, 2, 3} and a relation R is defined in X as : R = {(1, 3), (2, 2), (3, 2)}, then minimum ordered pairs which should be added in relation R to make it reflexive and symmetric are

(a) {(1, 1), (2, 3), (1, 2)}

(b) {(3, 3), (3, 1), (1, 2)}

(c) {(1, 1), (3, 3), (3, 1), (2, 3)}

(d) {(1, 1), (3, 3), (3, 1), (1, 2)}

Q11. A Linear Programming Problem is as follows:

Minimise     z = 2x + y

subject to the constraints
x ≥3 , x ≤9, y ≥ 0
x -y ≥ 0, x + y≤14

The feasible region has

(a) 5 corner points including (0, 0) and (9,5)

(b) 5 corner points including (7.7) and (3, 3)

(c) 5 corner points including (14, 0) and (9, 0)

(d) 5 corner points including (3, 6) and (9,5)

Q12. The function f(x) = e^3x – e^5x/x, if x  0 & k, if x = 0 is continuous at x = 0 for the value of k as

(a) 3

(b) 5

(c) 2

(d) 8

Q14. The function of y = x² e^x  is decreasing in the interval

(a) (0,2)

(b) (2, ∞)

(c) (-∞, 0)

(d) (-∞, 0) (2, ∞)

Q15. If R= {(x, y); x, y € z, x² + y² < 4} is a relation in set Z, then domain of R is

(a) {0, 1, 2}

(b) {-2, -1, 0, 1, 2}

(c) {0,-1, -2}

(d) {-1, 0, 1}

Q16. The system of linear equations

5x + ky = 5,

3x + 3y = 5;

will be consistent if

(a) k ≠ -3

(b) k = -5

(c) k = 5

(d) k ≠ 5

Q17. The equation of the tangent to the curve y (1 + x²) = 2 – x, where it crosses the x-axis is

(a) x – 5y = 2

(b) 5x – y = 2

(c) x+ 5y = 2

(d) 5x + y = 2

Q19. The principal value of tan^-1 (tan 9𝞹/8) is –

(a) 𝞹/8

(b) 3𝞹/8

(c) -𝞹/8

(d) -3𝞹/8

Section B

Q21.  The function f(x) = 2x³ – 15x² + 36 x + 6 is increasing in the interval

(a) (∞, 2) u (3, ∞)

(b) (-∞,2)

(c) (-∞, 2) u (3,∞)

(d) (3, ∞)

Q22. If x = 2 cosθ – cos 2θ and y = 2 sinθ – sin 2θ, then dy/dx is

(a) cos θ+cos 2θ/sin θ- sin 2θ

(b) cos θ-cos 2θ/sin θ- sin 2θ

(c) cos θ-cos 2θ/sin θ- sin 2θ

(d) cos θ-cos 2θ/sin 2θ+sin θ

Q23. What is the domain of the function cos^-1 (2x – 3) ?

(a) [-1, 1]

(b) (1, 2)

(c) (-1, 1)

(d) [1,2]

Q24. The number of elements in A which are more than 5, is

(a) 3

(b) 4

(c) 5

(d) 6

Q27. Let X = {x² : x € N} and the function f:N → X is defined by f(x) = x², x € N. Then this function is

(a) injective only

(b) not bijective

(c) surjective only

(d) bijective

Q28. The corner points of the feasible region for a Linear Programming problem are P(0, 5). Q(1, 5), R(4. 2) and S(12, 0). The minimum value of the objective function Z = 2x + 5y is at the point

(a) P

(b) Q

(c) R

(d) S

Q29. The equation of the normal to the curve ay^2 = x^3 at the point (am^2, am^3) is

(a) 2y – 3mx + am^3 = 0

(b) 2x + 3my – 3am^4 – am^2 = 0

(c) 2x + 3my + 3am^4 – 2am^2 = 0 (d) 2x + 3my – 3am^4 – 2am^2 = 0