## Maths Answer Key Class 12

Maths Class 12 Answer Key for Term 1: Today the Board Class 12 Mathematics Exam for Term-1 was conducted on 06th December 2021 and lakhs of 12th Class students have appeared in the exam. As the exam is over now, students must be rushing to know the correct responses to the Maths MCQ Questions asked in today's exam. We are providing the Answer Key of the Class 12 Maths Exam prepared by our expert faculty here so that the students can match their responses attempted in the exam. With the correct answers that are provided here, you can calculate how many marks can be expected in your term-1 board exam.

## Class 12 Maths Answer Key for Term-1

In this article, we have provided all the questions asked in the Maths Class 12 Term-1 Exam along with the solved Answer Key of Maths Class 12 to help the students to calculate the approximate marks to be secured in the Term-1 Exam. The Maths Class 12 Exam is divided into three sections with 50 questions out of which students have to appear for 40 questions (mandatory), for which the pattern decided by CBSE is as follows:

1. Section A consists of 20 questions and candidates have to attempt any 16 questions.

2. Section B consists of 20 questions and students have to attempt any 16 questions.

3. Section C consists of 10 questions and students have to attempt any 8 questions.

## Maths Class 12 Answer Key 2021

The official Maths Answer Key for Class 12 Term-1 can be tentaively released by CBSE once all subject exams are over. However, for the satisfaction of students, we have provided an Unofficial answer key of Maths Term-1 Class 12 here.

## Maths Class 12 Question Paper with Answer Key

The students who appeared in the Maths Class 12 MCQ Exam, can now cross-check their Answer Key for Class 12 Maths Paper which is provided here by our expert faculty. Stay tuned with us to get the correct responses to all the questions asked in today's exam through this Class 12 Maths Answer key of Set-4.

Section-A

Q1. Differential of log (log (log x^5)] w.r.t. x is

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

Q30. If A is a square matrix of order 3 and A| = -5, then adj Al is

(a) 125

(b) – 25

(c) 25

(d) ± 25