Practice Questions

Q77.In a class of 140 students numbered 1 to 140 , all even numbered students opted Mathematics course, those whose number is divisible by 3 opted Physics course and those whose number is divisible by 5 opted Chemistry course. Then the number of students who did not opt for any of the three courses is: (1) 42 (2) 1 (3) 38 (4) 102

Q77.The sum of the real roots of the equation 𝑥 -6 -1 2 -3𝑥 𝑥- 3 = 0, is equal to: -3 2𝑥 𝑥+ 2 (1) 0 (2) -4 (3) 6 (4) 1 JEE Main 2019 (10 Apr Shift 2) JEE Main Previous Year Paper

Q77. et e−tcos t e−t sin t If A = ⎡et −e−t cos t −e−t sin t −e−t sin t + e−t cos t ⎤, then A is: et 2e−t sin t −2e−t cos t ⎣ ⎦ (1) Invertible only if t = π (2) Not invertible for any t ∈R (3) Invertible only if t = π2 (4) Invertible for all t ∈R

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 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

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.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.An ordered pair (α, β) for which the system of linear equations (1 + α)x + βy + z = 2 αx + (1 + β)y + z = 3 αx + βy + 2z = 2 has a unique solution, is : (1) (−3, 1) (2) (1, −3) (3) (2, 4) (4) (−4, 2) JEE Main 2019 (12 Jan Shift 1) JEE Main Previous Year Paper

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.For 𝑥 𝜖 (0, 3 ), let 𝑓𝑥= 𝑔𝑥= tan𝑥 and ℎ𝑥= 1 - 𝑥2 . If ϕ𝑥= ( ho𝑓) og ) ( 𝑥) , then ϕ 𝜋 is equal to: 2 √𝑥, 1 + 𝑥2 3 𝜋 5𝜋 (1) tan⁡ (2) tan⁡ 12 12 7𝜋 11𝜋 (3) tan⁡ (4) tan⁡ 12 12

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 the system of equations x + y + z = 5, x + 2y + 3z = 9, x + 3y + αz = β has inifinitely many solutions, then β −α equals (1) 8 (2) 21 (3) 5 (4) 18 Q79. ⎡−2 4 + d (sin θ) −2 ⎤ Let d ∈R, and A = 1 (sin θ) + 2 d , θ ∈[0, 2π]. If the minimum value of det(A) is ⎣ 5 (2 sin θ) −d (−sin θ) + 2 + 2d ⎦ 8, then a value of d is: + + (1) 2(√2 2) (2) 2(√2 1) (3) −5 (4) −7 . Let S be the set of points in the interval (−4, 4) at which f is not

Q78.If the system of linear equations 𝑥- 2𝑦+ 𝑘𝑧= 1 2𝑥+ 𝑦+ 𝑧= 2 3𝑥- 𝑦- 𝑘𝑧= 3 has a solution 𝑥, 𝑦, 𝑧, 𝑧≠0, then 𝑥, 𝑦 lies on the straight line whose equation is: (1) 4𝑥- 3𝑦- 4 = 0 (2) 3𝑥- 4𝑦- 4 = 0 (3) 3𝑥- 4𝑦- 1 = 0 (4) 4𝑥- 3𝑦- 1 = 0

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.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.If the system of linear equations 2x + 2y + 3z = a 3x −y + 5z = b x −3y + 2z = c where, a, b, care non- zero real numbers, has more than onc solution, then (1) b −c + a = 0 (2) b −c −a = 0 (3) a + b + c = 0 (4) b + c −a = 0

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.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 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 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

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.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 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