Explore topic-wise InterviewSolutions in Current Affairs.

This section includes 7 InterviewSolutions, each offering curated multiple-choice questions to sharpen your Current Affairs knowledge and support exam preparation. Choose a topic below to get started.

1.

(dy)/(dx) = 3y cot x = sin 2x, y = 2 when x = (pi)/(2)

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Answer :`y = 4 SIN^(3)x - 2SIN^(2)x`
2.

Let O be the vertex and Q be any point on the parabola ,x^(2) =8y . If the point P divides the line segment OQ internally in the ratio 1: 3 then the locus of P is:

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`X^(2)=y`
`y^(2)=x`
`y^(2)=2X`
`x^(2)=2Y`

ANSWER :D
3.

In which of the following situations, it is possible to have a DeltaABC ? (All symbols used have usual meaning in a triangle)

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` (a+c-b) (a-c+b) =4bc`
`b^(2)SIN 2C+COS ^(2)sin2B=ab`
`a=3,b=5, c=7 and C =(2pi)/(3)`
`cos ((A-C)/(2))=cos ((A+C)/(2))`

ANSWER :B::C
4.

if O is the point inside the triangle ABC such that /_OBC = A/2, /_OCA = B/2, /_AOB = C/2, then (sin(A - C/2)sin(B - A/2)sin(C - B/2))/(sin""(A)/2 sin""(B)/2 sin""(C)/2) equal :

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`COS""A/2 cos""B/2 cos""C/2`
`sinA SINB sinC`
1
`COSA cosB cosC.`

Answer :C
5.

By rotating the coordinate axes in the positive direction about the origin by an angle alpha, if the point (1, 2) is transformed to ((3sqrt(3)-1)/(2sqrt(2)),(sqrt(3)+3)/(2sqrt(2))) in new coordinate system Then, alpha =

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`(pi)/(3)`
`(pi)/(6)`
`(pi)/(9)`
`(pi)/(12)`

ANSWER :D
6.

If 4x + y = 14 and 3x + 2y = 13, then x - y =

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ANSWER :`X - y = 1`
7.

Integrate the following functions: sin^4x

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Solution :`sin^4x = (SINX)^2 = ((1-cos2x)/2)^2`
= `1/4(1-2cos 2x +cos^2 2x)`
=`1/4(1-2cos 2x +(1+cos 4x)/2)`
`=1/8(2-4 cos2x+1+cos4x)`
`=1/8(3-4 cos2x+cos4x)`
therefore` INT sin^4x dx`
`=1/8[3x-4 (SIN2X)/2+(sin4x)/4]+c`
`=3/8x- 1/4sin2x + (sin4x)/(32)+c`
8.

If a,b,c in Rthen number of ordered triplet (a,b,c) which satisfy the equations a^(2)+2b=6,b^(2)+4c=-7andc^(2)+6a=-13is

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0
1
2
More than 2

Solution :`becausea^(2)+2b=6,b^(2)+4c=-7` and`c^(2)+6a=-13`
`impliesa^(2)+b^(2)+c^(2)+2b+4c+6a=-14`
`implies(a+3)^(2)+(b+1)^(2)+(c+2)^(2)=0`
`impliesa=-3,b=-1,c=-2`, but these VALUES does not SATISFY given equation
9.

Find the shortest distance between the following lines:(x-3)/1=(y-5)/(-2)=(z-7)/1and (x+1)/7=(y+1)/(-6)=(z+1)/1

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`SQRT(29)`
`2sqrt(29)`
`3sqrt(29)`
`5sqrt(29)`

ANSWER :B
10.

A function f :R to R is given by f (x) = {{:(x ^(4) (2+ sin ""(1)/(x)), x ne0),(0, x=0):}, then

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F has a continous DERIVATIVE `AA x in R`
f is a bounded function
f has an GLOBAL minimum at `x=0`
f" is continous `AA x in R`

ANSWER :A::C::D
11.

If z_(1) and z_(2) are two of the 8^(th) roots of unity such that arg(z_(1)/z_(2)) is last positive, then z_(1)/z_(2) is

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`1+i`
`1-i`
`(1+i)/sqrt(2)`
`(1-i)/sqrt(2)`

Solution :We know that the `n^(th)` ROOTS of unity lie on the circle `|z|=1` and divide its circumference into n equal parts.
ALSO, `n^(th)` roots of unity are given by
`z_(R) = (e^(i2rpi)/n),r=0 1,2,…..,(n-1)`
`therefore 8^(th)` roots of unity are given by `r=0,1,2,....,7`
We know that arg `(z_(1)/z_(2))="arg"(z_(1))-"arg"(z_(2))`. Therefore, arg`((z_(1))/z_(2))` will have least positive value, if `z_(1)` and `z_(2)` represent any two consecutive points on the circle `|z|=1`.
Let `z_(1)=z_(r)=e^((irpi)/4)`. Then, `z_(2)=z_(r-1)=e^(i(r-1)pi/4)`
`therefore z_(1)/z_(2)=e^(ipi//4)=cospi/4+isinpi/4=(1+i)/sqrt(2)`
12.

The second term of an A.P is (x - y) and fifth term is (x + y), then the first term is

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`X - 1/3y`
`x - 2/3y`
`x - 4/3y`
`x - 5/3y`

ANSWER :D
13.

The value (int_(0)^(pi//2) (sinx)^(sqrt2+1)dx)/(int_(0)^(pi//2)(sinx)^(sqrt2-1)dx) is -

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`(sqrt2+1)/(sqrt2-1)`
`(sqrt2-1)/(sqrt2+1)`
`(sqrt2+1)/(sqrt2)`
`s-sqrt2`

Solution :`I_(1)-overset(pi//2)underset(0)int(SIN X)^(sqrt2).sin"xdx"I_(2)=overset(pi//2)underset(0)int(sin x)^(sqrt2-1)"dx"`
`I_(1)=((SINX)^(sqrt2)intsin"x dx")_(0)^(pi//2)-overset(pi//2)underset(0)int(sqrt2(sinx)^(sqrt2-1)COSX intsin"x dx")`
`=-(cos x(sinx)^(sqrt2))_(0)^(pi//2)+sqrt2overset(pi//2)underset(0)int(sinx)^(sqrt2-1)(1-sin^(2)x)dx`
`(I_(1))/(I_(2))=(sqrt2)/(1+sqrt2)xx((sqrt2-1))/((sqrt2-1))=2-sqrt2`
14.

If f(x) is a polynomial in x(gt0) satisfying the equation f(x)+f(1//x)=f(x).f(1//x) then f(x)=

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`X^(N)`
`x^(n)+1`
`x^(n)-1`
1

Answer :B
15.

Find the middle term (s) in the expansion of (3x^2 + (5)/(x^3))^12

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ANSWER :`""^12C_6 ((15)/(X))^6`
16.

If f : R to R is defined by f (x) = 2x + 3 , then f^(-1) x

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ANSWER :No POINT of DISCONTINUITY
17.

Find the odd function f(x) such that the area bounded by the x -axis the curve y = f(x) and the lines x = - 1 and x = 1 is equal to in (t^(2) + 1), AA t ge 0.

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ANSWER :`+- (X)/(1 + x^(2))`
18.

If f(x)=(|x|)/(x)" for "x ne 0, f(0)=0," then f(x) at x=0 is "

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continuous
discontinuous
not determined
none

Answer :B
19.

i. Mean = a (3 median - mode) II. Mean - Mode = b(Mean - Median) (iii) Median = Mode + c (Mean - mode)

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`a LT C lt B`
`a lt b lt c`
`b lt c lt a`
`c lt a lt b`

ANSWER :A
20.

Two vertices of an equilateral triangle are (-1,0) and (1,0) then its circumcircle is

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`x^2 + (y - 1/(SQRT3))^2 = 4/3`
`x^2 + (y + 1/(sqrt3))^2 = 1/3`
`x^2 + (y - 1/(sqrt3))^2 + 4/9 = 0`
`x^2 + y^2 = 4/3`

ANSWER :A
21.

Let |bar(a)|=7, |bar(b)|=11, | bar(a)+bar(b)|=10 sqrt(3) What is the angle between (bar(a)+bar(b) and (bar(a)-bar(b))?

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`(pi)/(2)`
`(pi)/(3)`
`(pi)/(6)`
None of these

Solution :Let angle between `(vec(a)+vec(B)) and (vec(a)-vec(b)) ` be `ALPHA`
`cos alpha = ((vec(a)+vec(b))(vec(a)-vec(b)))/(|vec(a)+vec(b)||vec(a)-vec(b)|)`
`=((7)^(2)-(11)^(2))/(10sqrt(3)xx2sqrt(10))=((7+11)(7-11))/(20sqrt(3)xxsqrt(10))=(-18)/(5sqrt(30))`
`=(-6xx3)/(5sqrt(30))xx(SQRT(30))/(sqrt(30))=-(3sqrt(30))/(25)`
`alpha = cos ^(-1)((-3)/(5)sqrt((6)/(5)))`
22.

Integrate the rational functions (3x-1)/((x-1)(x-2)(x-3))

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ANSWER :`log|x-1|-5 log|x-2|+4log|x-3|+c`
23.

Find derivatives of the following functions.tan^3x

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SOLUTION :`y = TAN^3x = (tan X)
dy/dx = 3(tan x)^2. d/dx(tan x)
=3tan^2x.sec^2x`
24.

An isosceles triangle of a given perimeter 2p=12 revolves about its base. Write the function V(x), where V is the volume of the solid of revolution thus obtained and x is the length of the lateral side of the triangle.

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ANSWER :`V=8pi (X-3) (6-3), 3 LT x lt 6`
25.

Prove the following overset((pi)/(2)) underset(0) int sin^(3)xdx=(2)/(3)

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ANSWER :`(2)/(3)`
26.

If int (1)/(4 + 5 sin x) " dx "= (1)/(3) log |f (x)| + c then f(x) =

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`(2 TAN ""(x)/(2) -1)/(tan""(x)/(2) +2)`
`(2 + tan""(x)/(2))/(2 - tan""(x)/(2)) `
`(2 tan"" (x)/(2) + 1)/(2 ( tan""(x)/(2)+ 2)) `
`(tan""(x)/(2) - 1)/(2 tan""(x)/(2) + 3)`

ANSWER :C
27.

Find derivatives of the following functions.sin^2 x cos^2 x

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Solution :`y = sin^2 X .cos^2 x = 1/4sin^2 2X
dy/dx = 1/4 d/dx(sin2x)
= 1/4. 2SIN2X. d/dx(sin2x)
=1/2sin2x.cos2x. d/dx(2x)
= 1/2 sin2x .cos2x.2 = sin2x. cos2x`
28.

Find the area bounded between the curves y^(2)=4ax , x^(2) = 4by (a gt 0, b gt 0).

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ANSWER :`(16)/(3)` ab SQ. UNITS
29.

Statement 1 : Equation of the pair of lines bisecting the angle between the pair of lines ax^2+by^2+2hxy+2gx+2fy+c=0 can be written as x^2-y^2-((a-b)/h) xy +lamdax+muy+c'=0 because Statement 2 : Equation of any pair lines parallel to the lines ax^2+by^2+2hxy=0 is ax^2+2hxy+by^2+Ax+By +c''=0 .

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Statement - 1 is True, Statement -2 is True, Statement -2 is a correct explanation for statement - 1
Statement - 1 is True, Statement -2 is True, Statement -2 is NOT a correct explanation for Statement - 1
Statement -1 is True, Statement -2 is False
Statement -1 is False , Statement -2 is True

ANSWER :B
30.

A and B each select one number at random from the distinct numbers 1, 2, 3, …., n and the probability that the number selected by a is less than the number selected by B is (1009)/(2019). Now the probability that the number selected by B is the number immediately next to the number selected by A is

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`(2018)/(2019)`
`2018/((2010)^(2)`
`2000/((2019))`
`2000/((2019)^(2))`

Answer :B
31.

If sum _(x =pi-"" ^(10)C_(r))^(pi + "" ^(10)C _(r))sin x ^(0) =0, then value of r is "_________"

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ANSWER :3
32.

veca,vecb,vecc be three vectors such that V_(1)=[(veca, vecb, vecc)]=1and V_(2)=[(vecaxxvecb)xxvecc(vecbxxvecc)xxveca(veccxxveca),vecb)] then the value of sum_(r=1)^(6)V_(1)^(r)+V_(1)V_(2)^(r) is

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3
12
6
24

Solution :`V_(1)=1,V_(2)=0` (`:'` coplanar VECTORS)
33.

Ifthe chord joining two points whose eccentric angles are alpha and beta cut the major axis of an ellipse (x^(2))/(a^(2))+(y^(2))/(b^(2))=1 at a distancefrom the centre then tan (alpha)/(2).tan (beta)/(2) =

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`(1+e)/(1-e)`
`(e+1)/(e-1)`
`(e-1)/(e+1)`
both 2&3

Answer :D
34.

Integral part of the area of figure bounded by the tangents at the end of latus rectum of ellipse (x^(2))/9+(y^(2))/4=1 and directices of hyperbola (x^(2))/9=(y^(2))/72=1is

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Solution :Tangent at `(sqrt(5),4/3)` is `sqrt(5)x+3y=9x=1` is DIRECTRIX of Hyperbola.
So, `A=(1,(9-sqrt(5))/3)` & `B=(0,3)`
AREA of figure `OGAB` is
`1xx((9-sqrt(5))/3)+1/2xx1xx(3-(9-sqrt(5))/3)`
`=(9-sqrt(5))/3+(sqrt(5))/6`
`=(18-sqrt(5))/6`
Area of required figure is
`4{(18-sqrt(5))/6}=(36-2sqrt(5))/3`
Integral part of area is `7`
35.

Areabounded bythe ellipse(x^2 )/(4)+(y^2)/(16)=4 is …….

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`64 PI`
`32 pi`
`8pi`
`(pi)/(64)`s

Answer :B
36.

Given P=[[2,-3],[-1,2]] . Findthe inverse of P by elementary row operation.

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SOLUTION :`A^(-1) = [(2,3),(1,2)]`
37.

Find the n ^(th) term of the series 1,3,8,16,27,41,……

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ANSWER :`[3N ^(2) - 5N +4]`
38.

An oil company has two depots A and B with capacities of 7000L and 4000L respectively. The company is to supply oil to three petrol pumps, D,E and F whose requirements are 4500L,3000L and 3500L respectively. The distances (in km) between the depots and the petrol pumpa is given in the following table: Assuming that the transportation cost of10 litres of oil is Rs. 1 per km, how shold the delivery be scheduled in order that the transportation cost is minimum? What is the minimum cost?

Answer»

Solution :Let the supply of petrol from A to D be `x` litres and A to E be `y` litres. So the supply of petrol from A to F will be `(7000-x-y)` litres. Similarly, the supply of petrol from B to D,E,F will be `(4500-x)` litres, `(3000-y)` litres, `(x+y-3500)` litres respectively.
THEREFORE, minimum transportation cost.
`Z=1/10[7x+5y+3(7000-x-y)+3(4500-x)`
`+4(3000-y)+2(x+y-3500)]`
`=1/10(3x+y+39500)`
and CONSTRAINTS `xge0yge0`
`7000-x-yge0impliesx+yle7000`
`4500-xge0impliesxle4500`
`3000-yge0impliesyle3000`
`x+y-3500ge0impliesx+yge3500`
First, draw the graph of the lines `x+y=7000, x=4500,y=3000,x+y=3500`.

Now, we find the feasible region by constraints `x+yge7000,xle4500,yle3000,x+yge3500,xge0,yge0` and shade it whose VERTICES are `A(3500,0),B(4500,0),C(4500,2500),D(4000,30000,E(500,3000)`. We find the value of `Z` at these vertices.

`:. x=500,y=3000`
Therefore the supply of petrol form A to D,E,F will be 500 litres, 3000 litres, 3500 litres respectively and from B to D,E,F will be 4000 litres, 0 litres, 0 litres respectively.
Minimum transportation cos `=Rs. 4400`
39.

Evaluate the integral underset(0)overset(pi)int (1+cosx)^(3) dx

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ANSWER :`(5PI)/(2)`
40.

If z =e^((x +y)/(x -y)) then x (del xz)/(del x) + y (del z)/(dely)=

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2
0
1
`-1`

ANSWER :B
41.

An equilateral triangle with side a revolves about an axis parallel to the base and situated at a distance b gt a from the base. Find the volume of the solid of revolution.

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ANSWER :`pi ((a^(2)b SQRT3)/(2) + (a^(3))/(4))`
42.

Letintsqrt((5-x)/(2+x))dx equal

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`SQRT(x+2)sqrt(5-x)+3sin^(-1)sqrt((x+2)/(3))+C`
`sqrt(x+2)sqrt(5-x)+7SIN^(-1)sqrt((x+2)/(7))+C`
`sqrt(x+2)sqrt(5-x)+5sin^(-1)sqrt((x+2)/(5))+C`
none of these

Answer :b
43.

Let A = {1, 2, 3}, B { 4, 5, 6} and let f = {(1,4),(2,5)(3,6)} be a functionfrom A to B. Show that f is one-one.

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SOLUTION :F(1) = 4, f(2) = 5, f(3) =6. For distinct IMAGES.
`therefore` f is one-one
44.

Choose the correct answer int((10x^(9)+10^(x)log_(e)10) dx)/(x^(10)+10^(x)) equals

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`10^(X)-x^(10)+C`
`10^(x)+x^(10)+C`
`(10^(x)-x^(10))^(-1)+C`
`LOG(10^(x)+x^(10))+C`

Answer :D
45.

f(x) is a twice differentiable function such that f"(x)=-f(x) and f'(x)=g(x). If h(x)=(f(x))^(2)+(g(x))^(2) and h(l)=2, then h(2)=

Answer»

A.0
B.1
C.2
D.4

Answer :C
46.

Let y=x^(3)-8x+7 and x=f(t) given t=0, x=3 Find the value of (dy)/(dt).

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-2
2
`(1)/(2)`
`-(1)/(2)`

ANSWER :B
47.

A circle with center (2,1) has a tangent to the circle at (3,6). The equation of the tangent is

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5y-x=27
y+5x=21
x+5y=21
5y+x=33

Answer :D
48.

Integration using trigonometric identities : int(1)/(1+sin^(2)x)dx=....

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`(1)/(SQRT(2))TAN^(-1)(sqrt(2)tanx)+K`
`sqrt(2)tan^(-1)(sqrt(2)tanx)+k`
`-(1)/(sqrt(2))tan^(-1)(sqrt(2)tanx)+k`
`-sqrt(2)tan^(-1)(sqrt(2)tanx)+k`

Answer :A
49.

Find the values of k if area of triangle is 4 sq. units and vertices are(k,0),(4,0),(0,2)

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SOLUTION :Given that`Delta=+-4`
`implies1/2|[K, 0,1],[4, 0,1],[0, 2,1]|=+-4`
`1/2[1/2|[k,1],[4,1]|]=+-4`
(on expanding ALONG `C_2`)
`implies -(k-4)= +-4`
`implies 4-k= +-4 `
`implies k=4overset-+4=4-4` or
4+4=0 or 8
50.

""^((2n + 1))C_0 + ""^((2n+ 1))C_1 + ""^((2n + 1))C_2 + ……+""^((2n + 1))C_n =

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`2^n`
`2^(-n)`
`2^(2N)`
`3^(2n)`

ANSWER :C