Q01.The general solution of the differential equation () 2 2 xdy - ydx = x + y dy is:
Correct answer: () y x tan y C = +
Q02.If a curve y = (x) f passes through the point () 1, -1 and satisfies the differential equation () y 1+ xy dx = x dy, then -1 2 f is equal to:
Correct answer: 4/5
EnglishBihar (TRE 1.0) -2023
Q03.The integral surface satisfying the equation ∂ ∂ 2 2 z z y + x = x + y x y and passing through the curve x = 1 – t, y = 1 + t, z = 1 + t2 is
Correct answer: z = xy + () 2 2 2 1 x y 8 −
EnglishBihar (TRE 1.0) -2023
Q04.Let the general integral of the partial differential equation () () () ∂ ∂ 2 z z 2xy -1 + z - 2x = 2 x - yz z y be given by F(u, v) = 0, where F: R2 → → R is a continuously differentiable function. (R is the set of all real numbers and R2 = {(x, y): x, y ∈ R}) Then which of the following is true?
Correct answer: u = x2 + y2 + z, v = xz + y
EnglishBihar (TRE 1.0) -2023
Q05.The partial differential equation () 2 2 2 ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ 2 2 u u u 1 u u x + x - y - y + - = 0 x y 4 y x x y is
Correct answer: parabolic along the line x + y = 0
EnglishBihar (TRE 1.0) -2023
Q06.Consider the wave equation ∂ ∂ 2 2 u u = 4,0 < x < π,t > 0 t x with u (0, t) = u (π, t) = 0, u(x, 0) = sin x and ∂ u = 0 t at t = 0. Then u π, 2 2 is
Correct answer: – 1
EnglishBihar (TRE 1.0) -2023
Q07.The equation (αxy3 + y cos x)dx + (x2 y2 + βsinx) dy = 0 is exact for
Correct answer: α = 2, 1 3 β =
EnglishBihar (TRE 1.0) -2023
Q08.An integrating factor of x () -2x dy + 3x +1 y = xe dx is
Correct answer: xe3x
EnglishBihar (TRE 1.0) -2023
Q09.The differential equation representing the family of circles touching y-axis at the origin is
Correct answer: non-linear and of first order
EnglishBihar (TRE 1.0) -2023
Q10.Let, f, g: [– 1, 1] → → → R, f(x) = x3, g(x) = x2 |x|. Then
Correct answer: f and g are linearly independent on [– 1, 1]
Q11.If a and b are two odd prime numbers such that a > b, then a2 – b2 is:
Correct answer: an even number
Q12.3.13113111311113... is
Correct answer: an irrational number
Q13.Solution of the differential equation dy ycot x 4x cosecx dx + =, is:
Correct answer: 2 ysin x 2x c = +
Q14.The solution of the differential equation () 2 2 dy 1 x 1 y 0 dx + + + =, is:
Correct answer: 1 1 tan x tan y c − − + =
Q15.A solution of the differential equation x dy -y dx = 0 represents:
Correct answer: straight line passing through origin.
Q16.Which of the following equation is homogeneous differential equation?
Correct answer: y dy y x cos ycos x x dx x = +
Q17.Which of the following is a linear differential equation?
Correct answer: () 4 y y xy"' cosx e + + =
Q18.The solution of the differential equation (x + y + 1) dy 1 dx = is:
Correct answer: x = cey − y − 2
Q19.The order and degree of the differential equation y = dy 2 x dy dx + is:
Correct answer: 1, 2
Q20.Solution of the differential equation (x+2y3)dy=y dx, is:
Correct answer: x=y3 +cy