Q61.The steady state solution µ(x, t) = µs (x) of heat equation µt = a2 µxx satisfying the conditions µ (a, t) = –1, µ (2, t) = 1 is:
Correct answer: () s x –1 x µ = +
Q62.The order and degree of the differential equation x2 (dx)2 + 2xydxdy + y2 (dy)2 – z2 (dz)2 = 0 are respectively:
Correct answer: 1 and 2
Q63.Which of the following can be reduced to a Clairaut's equation?
Correct answer: y = 2xp + y2 p3, where p = dy dx
Q64.The equation of the characteristic curve of the one-parameter family (x –a)2 + (y – a)2 + z2 = 1 is:
Correct answer: (x – y)2 = 2 (1 – z2)
Q65.The partial differential equation by eliminating the arbitrary function f from z = emx f (x + y) is:
Correct answer: p – q = mz
Q66.If x and e–x are two linearly independent solutions of the equation () 2 2 2 d y dy 1+ x + x – y dx dx () 2 = 1+ x, then by the method of variation of parameter, the particular integral is:
Correct answer: x2/+ 1 – x
Q67.The integral surface of of yp + xq – z = 0 passing through the curve z = x3, y = 0 is:
Correct answer: () ()() 2 2 2 2 z 1+ x – y = x – y x + y + z
Q68.The particular integral of the equation (2D2 – D')z = 10ex–3y is:
Correct answer: 2ex – 3y
Q69.The integral curves of the equation () 2 3 3 dx = x y – z () () 2 3 3 2 3 3 dy dz = y z – x z x – y are given by: Where c1 and c2 are arbitrary constants.
Correct answer: x2 + y2 + z2 = c1 and x–1 + y–1 +z–1 = c2
Q70.The differential equation for the family of surfaces x3 z + x2 y = c, where c is a parameter, is:
Correct answer: (3xz + 2y)dx + xdy + x2 dz = 0
Q71.The general solution of the differential equation x 1 y" – y'+ y = 0 x –1 x –1 is:
Correct answer: y = c1x – c2ex
Q72.If the roots of the auxiliary equation of the differential equation 4 2 2 4 3 2 d y d y d y dy – 5 + 6 + 4 dx dx dx dx –8y = 0 are 2, 2, 2 and –1, then the general solution is:
Correct answer: y = (c1 + c2x + c3x2)e2x + c4e–x
Q73.Which of the following is a Cauchy-Euler equation?
Correct answer: 3 2 d y d y dy x – 4x +8x – 8y = 4 dx dx dx lnx
Q74.If y = y1 (x) is not a known solution, then by the removal of the first derivative, the general solution of y" + P (x) y' + Q(x) y = R(x) is obtained, where y1 is given by:
Correct answer: 1 – Pdx 2 e ∫
Q75.The solution of the differential equation dy 2x y 3 dx represents–
Correct answer: parabola
Q76.Differential equation for y = A cos αx + B sin αx, where A and B are arbitrary constants, is–
Correct answer: 2 d y y 0 dx
Q77.The integrating factor of 3 dy y x 3 dx x is–
Correct answer: x
Q78.The solution of 1 3 dy y dx x is–
Correct answer: 2 2 3 3 y x C
Q79.Shooting method is used to solve:
Correct answer: Only boundary value problems
Q80.In recurrence relation r 2 r 1 r a 2a a, 0 a 2, 1 a 1, the ar is given by:
Correct answer: r/1 2r 2