EnglishBihar (TRE 1.0) -2023
Q01.The function f(x, y) = 3x2 y + 4y3 – 3x2 – 12y2 + 1 has a saddle point at.
Correct answer: (–2, 1)
EnglishBihar (TRE 1.0) -2023
Q02.Let f(x, y) = 2 2 2 x y x + y for (x, y) ≠ (0, 0) then
Correct answer: More than one of the above
EnglishBihar (TRE 1.0) -2023
Q03.Let α = ∞ ∫ 2 0 1 1+ t at Which of the following is true?
Correct answer: sin (α) = 1
Q04.∫ 2 2 dx sin x.cos x equals
Correct answer: tanx – cotx + c
Q05.Find the directional derivation of Du f(x, y) at the point (x, y) = (1, 2), where f (x, y) = x3 – 3xy + 4y2 and u is the unit vector in the direction θ = π/6.
Correct answer: 13 – 3 3/2
Q06.Evaluate lim(x,y,z)→ → →(3,0,1)exp–xy sin(xy/z):
Correct answer: 0
Q07.() () → 3 3 x,y 0,0 x + y lim x – y
Correct answer: Does not exist
EnglishUPPSC Polytechnic Lecturer 2021 (I)
Q08.If 2 xy z = e,x = tcost,y = tsint, then the value of dz π at,t = is - dt 2
Correct answer: 3 – 8 π
EnglishUPPSC Ashram Paddhati 2021
Q09.If u = () 2 2 2 3 3 2 2 x (x – y) x + y, the value of ∂ ∂ ∂ u u x + y y x is
Correct answer: 2u
EnglishUPPSC Ashram Paddhati 2021
Q10.If u is a homogeneous function of x and y of degree n, the value of ∂ ∂ ∂ ∂ ∂ 2 2 2 2 2 u u u x + 2xy + y x y is
Correct answer: n(n – 1)u
Q11.If V = (x2 + y2 + z2)–1/2, then ∂ ∂ ∂ ∂ ∂ ∂ V V V x + y + z x y z is equal to
Correct answer: –V
Q12.If u = x y +, then the value of 2 2 2 2 2 2 u u u x xy y, x y ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ + + ∂ ∂ is -
Correct answer: −u/4
Q13.If u = f (y/x), then the value of u u x y ∂ ∂ + ∂ ∂ is –
Correct answer: 0
EnglishUP PGT 2021 UP PCS (Pre) 1994 Rajsthan TGT 2011
Q14.If u = sin–1 2 2 + y x, then x ∂ ∂ u u + y y x is equal to –
Correct answer: tan u
EnglishUPPSC Polytechnic Lecturer 2021 (I)
Q15.If L= → 2 2 (x,y) (0,0) sin(x + y) lim x + y and () → 2 2 (x,y) (0,0) x – y M = lim,then - x + y
Correct answer: L exists but M does not exist
Q16.() () () –1 x,y 2,1 sin xy – 2 lim tan 3xy – 6 → is equal to –
Correct answer: 1/3
EnglishUP Higher Asst. Prof. 2021
Q17.For the function f(x,y) defined as () 2 2 4 xy,if x,y 0 x y f(x,y) 0,if x,y 0 ≠ + = at the origin directional derivative
Correct answer: exists and f(x) is not continuous.
EnglishDSSSB TGT 04-09-2021 Shift-I (Male)
Q18.Find the maximum value from the extreme values of this function: u = x2 y2 – 5x2 –8xy–5y2
Correct answer: (0,0)
Q19.If z = f(x + ay) + φ(x – ay), then.
Correct answer: Formula option B (see source)
Q20.→ y x x y x - y lim x - y =
Correct answer: e 1 log y 1 log y − +