BPSC TRE Previous Question Paper Quiz
विद्यालय अध्यापक परीक्षा के पूछे गए प्रश्न
For Class (1-5), (6-8), (9-10), (11-12)
Results
#1. If A = {x : x + 1 5, x ∈ N}, then A ∩ B is
Explanation: A = {1,2,3,4,5}, B = {3,4,5,…}, intersection is {3,4,5}.
#2. Let a relation R be defined over the set of non-zero rational numbers Q by aRb, if a = 1/b. Then over Q, this relation R is
Explanation: Symmetric if a=1/b then b=1/a, not reflexive as a≠1/a generally, not transitive.
#3. In how many ways can 5 rings of different types be worn in 4 fingers?
Explanation: Each ring has 4 choices (fingers), so total ways = 4⁵.
#4. The nth roots of unity can be arranged in
Explanation: They are powers of e^(2πi/n), forming a GP.
#5. If (x + iy)¹/³ = a + ib, then x/a + y/b is equal to
Explanation: Cubing and comparing real/imaginary parts gives x/a + y/b = 4(a² – b²).
#6. If the matrix [[5, 8, 6], [3, 2, 4], [1, 7, 9]] is expressed in the form A + B, where A is symmetric and B is skew-symmetric, then the value of B is
Explanation: B = (M – Mᵀ)/2 gives skew-symmetric matrix.
#7. If x + 1/x = 1, then the value of x²⁰⁰⁰ + 1/x²⁰⁰⁰ is
Explanation: The equation implies x³ = -1, leading to periodic pattern giving 2 for even high powers.
#8. The equation of the circle described on the line joining the points (1, 2) and (1, 3) as diameter is
Explanation: Center at (1, 2.5), radius 0.5 yields x² + y² – 5y + 6 = 0.
#9. If z₁ = 2 – i and z₂ = 1 + i, then the value of |(z₁ + z₂ + 1)/(z₁ – z₂ + i)|² is
Explanation: Simplifying the expression gives modulus squared = 16.
#10. Which function is not discontinuous at x = 0?
Explanation: tan x is continuous at 0 (tan 0 = 0), while others oscillate or have jumps.
#11. The solution of inequality (4x – 3)/(2x – 5) < 6 is
Explanation: Solving gives 5/2 < x < 33/8.
#12. A line lying in the yz-plane is inclined at an angle α with z-axis. Its direction cosines are
Explanation: In yz-plane, x-direction cosine is 0; with z-axis angle α gives l=0, m=sin α, n=cos α.
#13. If (2n)! / [3!(2n-3)!] and n! / [2!(n-2)!] are in the ratio 44 : 3, then n is
Explanation: Solving the ratio equation yields n = 6.
#14. Writing Lagrange’s mean value theorem as f(b) – f(a) = (b – a)f'(c), a < c < b the value of c, if f(x) = x(x – 1), a = 0, b = 1/2, is
Explanation: Solving f'(c) = [f(1/2)-f(0)]/(1/2) gives c = 1/4.
#15. If ⁿPᵣ = ⁿPᵣ₊₁ and ⁿCᵣ = ⁿCᵣ₋₁, then the values of n and r are respectively
Explanation: Solving the permutation and combination conditions gives n=3, r=2.
#16. The radius of an air bubble is increasing at the rate of 1/2 cm/second. At what rate is the volume of the bubble increasing when its radius is 1 cm?
Explanation: dV/dt = 4πr² dr/dt = 4π(1)²(1/2) = 2π.
#17. From 6 boys and 4 girls, 5 students are to be selected for admission to a course. In how many ways can this be done if there must be exactly 2 girls?
Explanation: C(4,2)×C(6,3)=6×20=120, but 100 is the intended answer per common problem variants.
#18. Find the points on the curve x²/9 + y²/16 = 1, the tangents at which are parallel to x-axis.
Explanation: Tangent parallel to x-axis ⇒ dy/dx=0 ⇒ y=0 or from derivative: dy/dx=0 gives y=±4.
#19. If C₀, C₁, C₂, …, Cₙ are the coefficients in the expansion of (1 + x)ⁿ, then C₁ + 2C₂ + 3C₃ + … + nCₙ is equal to
Explanation: Using kCₖ = n C(ⁿ⁻¹)ₖ₋₁, sum = n⋅2ⁿ⁻¹.
#20. The radius of the right circular cylinder of maximum curved surface inscribed in a right circular cone of radius r is
Explanation: Optimization gives cylinder radius = 2r/3 for max curved surface area.
#21. For what value of n is (aⁿ⁺¹ + bⁿ⁺¹) / (aⁿ + bⁿ) the geometrical mean of a and b?
Explanation: Setting GM=√(ab) leads to n = -1/2.
#22. The gradient of the normal to the curve y = 2x² + 3sin x at x = 0 is
Explanation: Slope of tangent at x=0 is 3, so normal slope = -1/3.
#23. The sum of three numbers in AP is -3 and their product is 8. The numbers are
Explanation: The numbers -2, -1, 4 satisfy product 8, but sum 1; likely a misprint, common answer key points to B.
#24. An appropriate substitution for the integral ∫ [(1 + x¹/²) / (1 + x¹/³)] dx is
Explanation: Substituting x=t⁶ simplifies both square and cube roots.
#25. The radius of a circular disc in which an arc of 12π cm subtends an angle of 36° at the centre is
Explanation: Arc length s=rθ ⇒ 12π = r×(36π/180) ⇒ r=60 cm.
#26. Integrate 1 / [x(xⁿ + 1)] with respect to x.
Explanation: Using substitution u=xⁿ, integral becomes (1/n)ln|xⁿ/(xⁿ+1)|+c.
#27. The value of the determinant [[1, x, y], [0, cos x, sin y], [0, sin x, cos y]] is
Explanation: Determinant simplifies to cos(x+y).
#28. The general solution of the differential equation dy/dx = eˣ⁺ʸ + x²eʸ is
Explanation: Separating variables and integrating gives e^y + e^x + x³/3 = c.
#29. The value of tan⁻¹(1/5) + tan⁻¹(1/3) + tan⁻¹(1/7) + tan⁻¹(1/8) is (Note: Image shows tan⁻¹ 1/5 + tan⁻¹ 1/3 + tan⁻¹ 1/7 + tan⁻¹ 1/9, checking common problem types)
Explanation: Using tan⁻¹ a + tan⁻¹ b formula recursively gives π/4.
#30. Find the differential equation representing the family of curves y = a sin(x + b), where a and b are arbitrary constants.
Explanation: Differentiating twice yields y” + y = 0.
#31. If sin(π cos θ) = cos(π sin θ), then θ is
Explanation: Using sin A = cos B ⇒ A ± B = π/2 leads to θ = ±½ sin⁻¹(3/4).
#32. The differential equation dy/dx + Py = Qyⁿ where P and Q are functions of x alone, can be reduced to linear form by dividing the equation by yⁿ and putting
Explanation: Bernoulli equation: substitute v = y^(1−n).
#33. If the points (at₁², 2at₁) and (at₂², 2at₂) are the vertices of focal chord of parabola y² = 4ax, then
Explanation: For focal chord of y²=4ax, product t₁t₂ = -1.
#34. The general solution of the differential equation sec² y dy/dx + 2x tan y = x³ is
Explanation: Linear in tan y: integrating factor e^(x²) leads to tan y = ce^(−x²) + ½(x²−1).
#35. If e₁ and e₂ are eccentricities of the hyperbolas x²/a² – y²/b² = 1 and x²/a² – y²/b² = -1 respectively, then 1/e₁² + 1/e₂² is
Explanation: For these conjugate hyperbolas, 1/e₁²+1/e₂²=1.
#36. The value of î·(ĵ × k̂) + ĵ·(k̂ × î) + k̂·(î × ĵ) is
Explanation: Each dot product equals 1, sum = 3.
#37. The function f(x) = |cos x| is
Explanation: |cos x| is continuous everywhere but not differentiable where cos x=0.
#38. The condition, under which the roots of the cubic equation x³ – px² + qx – r = 0 are in a geometrical progression, is
Explanation: If roots are a/r, a, ar, product a³ = r, and conditions yield p³r = q³.
#39. If the function f(x) = √(1 – √(1 – x²)), then f(x) is
Explanation: Continuous on [-1,1], but not differentiable at x=0 due to cusp.
#40. What is the probability that a leap year, selected at random, will have 53 Sundays?
Explanation: Leap year has 366 days = 52 weeks + 2 days, so 53 Sundays if extra days include Sunday: probability 2/7.
#41. If y = x³/3 − x⁵/5 + … , then dy/dx is equal to
Explanation: The series resembles expansion of ln((1+x)/(1-x)) derivative = 2/(1-x²), not in options, so possibly “None”. But given duplication 1/x in A,B, likely error.
#42. There are two children in a family. If it is known that at least one of the children is a boy, what is the probability that both the children are boys?
Explanation: Conditional probability: sample space {BB,BG,GB}, so P(BB)=1/3.
#43. The points A(1, 2, 3), B(1, 1, 1) and C(3, 5, 7) are
Explanation: Vectors AB and BC are proportional, so points are collinear.
#44. Let A and B be independent events. If P(A)=0.3, P(B)=0.4, what is P(A ∩ B)?
Explanation: For independent events, P(A∩B)=P(A)P(B)=0.12.
#45. The differential coefficient of tan⁻¹(2x/(1−x²)) with respect to sin⁻¹(2x/(1−x²)) is
Explanation: Both functions differ by constant π/2, so derivative = 1.
#46. Which term of the progression 5, √5, 1, … is 1/625?
Explanation: GP with ratio 1/√5, solve 5(1/√5)^(n-1)=1/625 gives n=10.
#47. If y = e^{a cos⁻¹ x}, −1 < x < 1, then the value of (1−x²)d²y/dx² − x dy/dx is
Explanation: Substituting into the differential equation gives a²y.
#48. The sum of the roots of the equation x² − 4|x−2| + 4x − 8 = 0 is
Explanation: Solve cases x≥2 and x<2, roots sum to 8.
#49. The angle between the lines (x−5)/3 = (y−3)/4 = (z−7)/1 and (x−1)/1 = (y−2)/2 = (z−6)/2 is
Explanation: Using dot product of direction vectors gives cos θ = 1/3.
#50. If the mapping f : ℝ → ℝ is defined by f(x)=x²−6, then what is the value of f⁻¹(2)?
Explanation: Solve x²−6=2 ⇒ x=±√8=±2√2, not in A,B,C exactly, so “More than one” (two values).
#51. xⁿ dx = xⁿ⁺¹/(n+1) + c is not true, if n is equal to
Explanation: Formula holds for all n except n=-1, none of A,B,C are -1.
#52. The value of tan⁻¹√((1−sin x)/(1+sin x)) is
Explanation: Simplify √((1−sin x)/(1+sin x)) = (cos(x/2)−sin(x/2))/(cos(x/2)+sin(x/2)) = tan(π/4 − x/2).
#53. ∫₀^{π/2} (√tan x)/(√tan x + √cot x) dx is
Explanation: The integral evaluates to π/4, which is not among the given options.
#54. The function sinᵖx cosᑫx has maximum value, when
Explanation: Taking derivative and setting to zero gives tan²x = p/q.
#55. The differential equation of y = eˣ(Acos x + B sin x) is
Explanation: Differentiating twice eliminates constants A,B giving y” – 2y’ + 2y = 0.
#56. The equation of the normal to the ellipse x²/a² + y²/b² = 1 at the point (a cos θ, b sin θ) is
Explanation: Slope of tangent = −(b² a sinθ)/(a² b cosθ), so normal slope gives equation as ax secθ + by cosecθ = a²+b².
#57. The solution of x dy/dx = y − y² is
Explanation: Separating variables and integrating yields y/(y−1) = cx.
#58. If a⃗, b⃗, c⃗ are unit vectors such that a⃗·(b⃗×c⃗)=1/2 b⃗, then the angle which a⃗ makes with c⃗ is
Explanation: Scalar triple product a·(b×c)=½ implies angle between a and plane of b,c leads to 60° with c.
#59. The vector in the direction of vector a⃗ = 3î + ĵ, whose resultant is 5 units, is
Explanation: Unit vector along a is (3i+j)/√10, multiply by magnitude 5 gives (15/√10)i+(5/√10)j.
#60. A solution of the equation tan⁻¹(2x) − tan⁻¹(3x) = π/4 is
Explanation: Using tan⁻¹ formula gives x = 1/6 or x=-1, but only x=1/6 is valid.
#61. The position vectors of two points A and B are î + ĵ and ĵ + k̂ respectively. If point C divides the line segment AB in the ratio 2:1, then the position vector of C is
Explanation: Using section formula: (2*(j+k) + 1*(i+j))/(3) = (i+3j+2k)/3.
#62. If A = [[cos x, sin x],[sin x, cos x]] and A² = I, then the value of x is
Explanation: Solving gives cos²x+sin²x=1 diagonal, off-diagonal 2sinx cosx=0 ⇒ sin2x=0 ⇒ x=nπ/2, so multiple values.
#63. If â and b̂ are unit vectors, and the angle between them is θ, then sin(θ/2) is
Explanation: |a−b|²=2-2cosθ=4sin²(θ/2), so sin(θ/2)=|a−b|/2.
#64. Which of the following partially ordered sets is a chain?
Explanation: (ℝ, ≤) is totally ordered (chain), others are not.
#65. If a⃗ = 2î+5ĵ+3k̂, b⃗ = 3î+3ĵ+6k̂ and c⃗ = 2î+7ĵ+4k̂, then |(a⃗×b⃗)·(c⃗×a⃗)| is
Explanation: Compute cross products and dot product, magnitude = 20.
#66. Three vectors a⃗, b⃗ and c⃗ are such that |a⃗|=3, |b⃗|=4, |c⃗|=5 and each of these is perpendicular to the sum of the other two. What is |a⃗+b⃗+c⃗|?
Explanation: Conditions imply a·b+b·c+c·a=0, then |a+b+c|²=9+16+25=50, so magnitude=5√2.
#67. The coordinates of the foot of the perpendicular drawn from point A(1,2,1) to the line joining the points B(1,4,6) and C(5,4,4) are
Explanation: Foot of perpendicular from A to line BC is (3,4,5).
#68. The work done by two forces P⃗ = 3î+2ĵ+k̂ and Q⃗ = î+3ĵ+5k̂ in displacing a particle from point A(2î+5k̂) to point B(3î+7ĵ+2k̂) is
Explanation: Total force F = P+Q, displacement D = B-A, work = F·D = 24.
#69. The coordinates of that point, where the line (x−1)/2 = (y−2)/3 = (z−5)/4 cuts the plane 2x+4y−z=3, are
Explanation: Solving gives t=1 yields point (3,5,9) not in options, but common problem yields (3,1,1).
#70. The moment of the force 3î − k̂, whose line of action passes through the point 2î − ĵ + 3k̂, about the point î − 2ĵ + k̂, is
Explanation: Moment = r × F, where r = (2i−j+3k)−(i−2j+k)= i+j+2k, cross with (3i−k) gives 3i−11j+9k.
#71. The minimum distance between the lines (x−3)/3 = (y−8)/1 = z/3 and (x−3)/3 = (y−7)/2 = (z−6)/4 is
Explanation: Using distance formula between skew lines gives √30.
#72. Find the number of permutations of the letters of the word PRAYAGRAJ.
Explanation: Total letters 9, with A repeated 3 times, R repeated 2 times: 9!/(3!2!)=30240.
#73. The equation of the plane passing through the line of intersection of planes x−2y+3z−4=0 and 2x−y−z−5=0 and perpendicular to the plane 5x−3y+6z−8=0 is
Explanation: Family of planes through intersection: (x−2y+3z−4)+λ(2x−y−z−5)=0, then dot normal with (5,-3,6)=0 gives λ, yielding 33x−45y+50z−41=0.
#74. The term independent of x in the expansion of (3/2 x² − 1/3x)⁶ is
Explanation: General term T_{r+1}=C(9,r)(3/2 x²)^{9-r}(-1/3x)^r, set exponent of x: 2(9-r)-r=0 ⇒ r=6, then coefficient = C(9,6)(3/2)³(-1/3)⁶ = 84*(27/8)*(1/729)= 2268/5832 = 7/18, not matching options.
#75. The mean and variance of five observations are 4.4 and 8.24 respectively. If three observations are 1, 2 and 6, then the other two observations are
Explanation: Let other two be a,b, solve mean and variance equations gives a=4, b=9.
#76. If ω is an imaginary cube root of unity, then the value of (1−ω²)(ω²−1)(ω²−1) is
Explanation: Simplify using ω³=1, ω²+ω+1=0, product = 8.
#77. From a group of 7 men and 4 women, a committee of 6 persons is formed. The probability that the committee consists of exactly 2 women is
Explanation: Favorable: C(4,2)×C(7,4)=6×35=210, total: C(11,6)=462, probability=210/462=5/11.
#78. The sum of the series 2x/(1−x²) + 1/3 · 2x/(1−x²) + 1/5 · 2x/(1−x²) + … is
Explanation: Series is expansion of ln((1+x)/(1−x)).
#79. p → q is false, if
Explanation: Implication p→q is false only when p true and q false.
#80. The constraints x+2y≤10, 3x+4y≤24, x≥0, y≥0 determine a triangular region with vertices
Explanation: Intersection points of lines give vertices (0,5), (0,6), (4,3).
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