Practice Questions

Q78.Let 𝜆 be a real number for which the system of linear equations 𝑥+ 𝑦+ 𝑧= 6, 4𝑥+ 𝜆𝑦- 𝜆𝑧= 𝜆- 2 and 3𝑥+ 2𝑦- 4𝑧= - 5 has infinitely many solutions. Then 𝜆 is a root of the quadratic equation: (1) 𝜆2 + 3𝜆- 4 = 0 (2) 𝜆2 - 𝜆- 6 = 0 (3) 𝜆2 - 3𝜆- 4 = 0 (4) 𝜆2 + 𝜆- 6 = 0 – 1 𝑦 𝑦

Q78.If 𝑓𝑥= log𝑒 11 +- 𝑥𝑥, 1 + 𝑥2 (1) 𝑓𝑥2 (2) 2𝑓𝑥2 (3) – 2𝑓𝑥 (4) 2𝑓𝑥 sin𝑥 𝜋 then 𝑑𝑦 is equal to

Q78.If the system of linear equations x −4y + 7z = g; 3y −5z = h ; −2x + 5y −9z = k is consistent, then: (1) g + h + 2k = 0 (2) g + 2h + k = 0 (3) 2g + h + k = 0 (4) g + h + k = 0

Q78.The set of all values of λ for which the system of linear equations x −2y −2z = λx x + 2y + z = λy −x −y = λz has a non-trivial solution : (1) is an empty set (2) contains more than two elements (3) is a singleton (4) contains exactly two elements

Q78.The number of functions f from {1, 2, 3, … , 20} onto {1, 2, 3, … , 20} such that f(k) is a multiple of 3, whenever k is a multiple of 4 is: (1) 65 × (15)! (2) 5! × 6! (3) (15)! × 6! (4) 56 × 15

Q78.If cos-1 2 cos-1 3 𝜋 𝑥> 3 then 𝑥 is equal to : 3𝑥+ 4𝑥= 2 4, (1) √145 (2) √145 10 11 (3) √146 (4) √145 12 12 1 1

Q78.If the function f defined on ( 6 , π3 ) by f(x) = π { k, x = 4 (1) 1 (2) 1 2 (3) 2 (4) 1 √2

Q78.Let f(x) = x2, x ∈R . For any A ⊆R, define g(A) = {x ∈R : f(x) ∈A} . If S = [0, 4] , then which one of the following statements is not true? (1) g(f(S)) ≠S (2) f(g(S)) ≠f(S) (3) f(g(S)) = S (4) g(f(S)) = g(S)

Q78.Let N be the set of natural numbers and two functions f and g be defined as f, g : N →N such that n+1 2 , if n is odd f(n) = n if n is even { 2 , and g(n) = n −(−1)n. Then fog is: (1) onto but not one-one (2) Both one-one and onto (3) One-one but not onto (4) Neither one-one nor onto K be the set of all points

Q78.If the system of equations 2x + 3y −z = 0, x + ky −2z = 0 and 2x −y + z = 0 has a non-trivial solution (x, y, z), then xy + yz + xz + k is equal to (1) −14 (2) 21 (3) −4 (4) 34

Q79.If 𝑒𝑦+ 𝑥𝑦= 𝑒, the ordered pair 𝑑𝑦 𝑑2𝑦 at 𝑥= 0 is equal to 𝑑𝑥, 𝑑𝑥2 1 1 1 1 (1) - 𝑒, - 𝑒2 (2) - 𝑒, 𝑒2 (3) 1 - 1 (4) 1 1 𝑒, 𝑒2 𝑒, 𝑒2

Q79.If [x] denotes the greatest integer ≤x, then the system of linear equations [sinθ]x + [−cosθ]y = 0, [cotθ]x + y = 0 (1) has a unique solution if θ ∈( π2 , 2π3 ) ∪(π, 7π6 ) (2) have infinitely many solution if θ ∈( π2 , 2π3 ) ∪(π, 7π6 ) (3) has a unique if θ ∈( π2 , 2π3 ) and have infinitely (4) have infinitely many solutions if θ ∈( π2 , 2π3 ) many solutions if θ ∈(π, 7π6 ) and has a unique solution if θ ∈(π, 7π6 )

Q79.Let f be a differentiable function such that f(1) = 2 and f ′(x) = f(x) for all x ∈R. If h(x) = f(f(x)), then h′(1) is equal to : (1) 4e2 (2) 2e (3) 4e (4) 2e2

Q79.Let 𝑓𝑥= a𝑥 ( a > 0 ) be written as 𝑓𝑥= 𝑓1𝑥+ 𝑓2𝑥, where 𝑓1 ( 𝑥) is an even function and 𝑓2 ( 𝑥) is an odd function. Then 𝑓1𝑥+ 𝑦+ 𝑓1 ( 𝑥- 𝑦) equals: (1) 2𝑓1𝑥𝑓1𝑦 (2) 2𝑓1𝑥+ 𝑦𝑓1𝑥- 𝑦 (3) 2𝑓1𝑥𝑓2𝑦 (4) 2𝑓1𝑥+ 𝑦𝑓2𝑥- 𝑦

Q79.If cos-1𝑥- cos = 𝛼, where -1 ≤𝑥≤1, - 2 ≤𝑦≤2, 𝑥≤ then for all 𝑥, 𝑦, 4𝑥2 - 4𝑥𝑦cos𝛼+ 𝑦2 is 2 2, equal to : (1) 4cos2𝛼+ 2𝑥2𝑦2 (2) 4sin2𝛼- 2𝑥2𝑦2 (3) 2sin2α (4) 4sin2α

Q79.Let f : (−1, 1) →R be a function defined by f(x) = max{−|x|, −√1 −x2}. If at which f is not differentiable, then K has exactly (1) two elements (2) one element (3) three elements (4) five elements

Q79.If x = sin−1(sin 10) and y = cos−1 (cos 10), then y −x is equal to: (1) 10 (2) π (3) 0 (4) 7π

Q79.Let f : R →R be differentiable at c ∈R and f(c) = 0. If g(x) = |f(x)|, then at x = c, g is: (1) not differentiable (2) not differentiable if f '(c) = 0 (3) differentiable if f '(c) = 0 (4) differentiable if f '(c) ≠0 Q80. , x < 0 ⎧ sin(p+1)x+sinxx If f(x) = is continuous at x = 0 , then the ordered pair (p, q) is equal to: ⎨ q , x = 0 √x+x2−√x , x > 0 ⎩ x3/2 (1) (−32 , −12 ) (2) (−12 , 32 ) (3) ( 52 , 12 ) (4) (−32 , 12 )

Q79.Let ∑10k=1 f(a + k) = 16(210 −1), where the function f satisfies f(x + y) = f(x)f(y) for all natural numbers x, y and f(1) = 2. Then the natural number 'a' is: (1) 3 (2) 16 (3) 4 (4) 2

Q79.Considering only the principal values of inverse functions, the set A = {x ≥0 : tan−1(2x) + tan−1(3x) = π4 } (1) Is an empty set (2) Contains more than two elements (3) Contains two elements (4) Is a singleton

Q79.If 2𝑦= cot-1√3cos𝑥+ 2 ∀𝑥∈0, cos𝑥- √3sin𝑥 2, 𝑑𝑥 (1) 𝜋 - 𝑥 (2) 2𝑥- 𝜋 (3) 𝑥- 𝜋 (4) None of these 6 3 6

Q79.For 𝑥∈𝑅- 0, 1, let 𝑓1𝑥= 𝑥, 𝑓2𝑥= 1 - 𝑥 and 𝑓3𝑥= 1 - 𝑥 be three given functions. If a function, 𝐽𝑥 satisfies 𝑓2𝑜𝐽𝑜𝑓1𝑥= 𝑓3𝑥 then 𝐽𝑥 is equal to: (1) 𝑓3𝑥 (2) 1 𝑥𝑓3𝑥 (3) 𝑓1𝑥 (4) 𝑓2𝑥

Q79.Let f : R →R be defined by f(x) = x , x ∈R. Then the range of f is 1+x2 (1) [−12 , 12 ] (2) R −[−1, 1] (3) R −[−12 , 12 ] (4) (−1, 1) −{0} and g(x) = |η(x)| + f(x ∣). Then, in the interval (−2, 2), g is:

Q79.Let K be the set of all real values of x where the function f(x) = sin |x| −|x| + 2(x −π) cos |x| is not differentiable. Then the set K is equal to : (1) ϕ (an empty set) (2) (π} (3) {0} (4) {0, π}

Q79.The domain of the definition of the function f(x) = 1 + log10(x3 −x) is: 4−x2 (1) (−1, 0) ∪(1, 2) ∪(2, ∞) (2) (1, 2) ∪(2, ∞) (3) (−2, −1) ∪(−1, 0) ∪(2, ∞) (4) (−1, 0) ∪(1, 2) ∪(3, ∞) JEE Main 2019 (09 Apr Shift 2) JEE Main Previous Year Paper