Practice Questions

Q50.The mass percentage of nitrogen in histamine is ________

Q51.Let α and β be the roots of the equation x2 −x −1 = 0 . If pk = (α)k + (β)k, k ≥1, then which one of the following statements is not true? (1) p3 = p5 −p4 (2) p5 = 11 (3) (p1 + p2 + p3 + p4 + p5) = 26 (4) p5 = p2 ⋅p3

Q51.If the equation x2 + bx + 45 = 0, b ∈R has conjugate complex roots and they satisfy |z + 1| = 2√10, then (1) b2 −b = 30 (2) b2 + b = 72 (3) b2 −b = 42 (4) b2 + b = 12

Q51.The set of all real values of λ for which the quadratic equation (λ2 + 1)x2 −4λx + 2 = 0 always have exactly one root in the interval (0, 1) is : (1) (−3, −1) (2) (0, 2) (3) (1, 3] (4) (2, 4]

Q51.The number of real roots of the equation, e4x + e3x −4e2x + ex + 1 = 0 is: (1) 1 (2) 3 (3) 2 (4) 4

Q51.Let f(x) be a quadratic polynomial such that f(–1) + f(2) = 0. If one of the roots of f(x) = 0 is 3 , then its other root lies in (1) (−1, 0) (2) (1, 3) (3) (–3, –1) (4) (0, 1) 1 1 2 2 +

Q51.Consider the two sets: A = {m ∈R : both the roots of x2 −(m + 1)x + m + 4 = 0 are real } and B = [−3, 5) Which of the following is not true? (1) A −B = (−∞, −3) ∪(5, ∞) (2) A ∩B = {−3} (3) B −A = (−3, 5) (4) A ∪B = R

Q51.Let S , be the set of all real roots of the equation, 3x(3x −1) + 2 = |3x −1| + |3x −2|, then (1) contains exactly two elements. (2) is a singleton. (3) is an empty set. (4) contains at least four elements.

Q51.If α and β be two roots of the equation x2 −64x + 256 = 0. Then the value of 1 1 + ( β5 ) ( α5 ) JEE Main 2020 (06 Sep Shift 1) JEE Main Previous Year Paper (1) 2 (2) 3 (3) 1 (4) 4

Q51.Let α and β be two real roots of the equation (k + 1)tan2x −√2 ⋅λ tan x = (1 −k), where k(≠−1) and λ are real numbers. If tan2(α + β) = 50, then a value of λ is (1) 10√2 (2) 10 (3) 5 (4) 5√2

Q51.Let [t] denote the greatest integer ≤t. Then the equation in x, [x]2 + 2[x + 2] −7 = 0 has : (1) exactly two solutions (2) exactly four integral solutions (3) no integral solution (4) infinitely many solutions

Q51.If α and β are the roots of the equation, 7x2 −3x −2 = 0, then the value of α + β is equal to: 1−α2 1−β2 (1) 27 (2) 1 32 24 (3) 3 (4) 27 8 16

Q51.Let λ ≠0 be in R. If α and β are the roots of the equation, x2 −x + 2λ = 0 and α and γ are the roots of the equation, 3x2 −10x + 27λ = 0, then βγλ is equal to: (1) 27 (2) 18 (3) 9 (4) 36 a + b is equal to:

Q52.The value of 2π 2π 3 2π 2π ( 1+sin 9 −i cos 99 ) is (1) 1 (2) 1 2 (1 −i√3) 2 (√3 −i) (3) −12 (√3 −i) (4) −12 (1 −i√3)

Q52.If 3+isinθ , θ ∈[0 ,2 π], is a real number, then an argument of sinθ + icosθ is 4−icosθ (1) π −tan−1( 34 ) (2) π −tan−1( 43 ) (3) −tan−1( 43 ) (4) tan−1( 43 )

Q52.The value of 30 ( −1+i√31−i ) is : (1) 65 (2) 215 i (3) −215 (4) −215 i

Q52.Let f : R →R be such that for all x ∈R(21+x + 21−x), f(x) and (3x + 3−x) are in A.P., then the minimum value of f(x) is (1) 2 (2) 3 (3) 0 (4) 4

Q52.If a and b are real numbers such that (2 + α)4 = a + bα, where α = −1+i√32 , then (1) 9 (2) 24 (3) 33 (4) 57

Q52.Let a, b ∈R, a ≠0 be such that the equation, ax2 −2bx + 5 = 0 has a repeated root α, which is also a root of the equation, x2 −2bx −10 = 0. If β is the other root of this equation, then α2 + β2 is equal to: (1) 25 (2) 26 (3) 28 (4) 24

Q52.If α and β are the roots of the equation x2 + px + 2 = 0 and α1 and β1 are the roots of the equation + α1 ) is equal to : 2x2 + 2qx + 1 = 0, then (α −1α )(β −1β )(α + β1 )(β (1) 9 4 (9 + q2) (2) 49 (9 −q2) (3) 4 9 (9 + p2) (4) 94 (9 −p2)

Q52.Let z = x + iy be a non-zero complex number such that z2 = i|z|2 , where i = √−1, then z lies on the : (1) line, y = −x (2) imaginary axis (3) line, y = x (4) real axis

Q52.If Re( 2z+iz−1 ) = 1, where z = x + iy, then the point (x, y) lies on a (1) circle whose centre is at (−12 , −32 ) (2) straight line whose slope is −23 (3) straight line whose slope is 3 2 (4) circle whose diameter is √52

Q52.Let z be a complex number such that z+2i z−i = 1 and |z| = 52 . Then, the value of |z + 3i| is (1) √10 (2) 72 (3) 15 (4) 2√3 4

Q52.The region represented by {z = x + iy ∈C : |z|−Re (z) ≤1} is also given by the inequality (1) y2 ≥2(x + 1) (2) y2 ≤2(x + 12 ) (3) y2 ≤(x + 12 ) (4) y2 ≥x + 1

Q52.If the four complex numbers z, z, z −2 Re (z) and z −2 Re (z) represent the vertices of a square of side 4 units in the Argand plane, then |z| is equal to : (1) 4√2 (2) 4 (3) 2√2 (4) 2