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4601.

Prove that (.^(n)C_(1)sin2x+.^(n)C_(2)sin4x+.^(n)C_(3)sin6x+"…..")/(1+.^(n)C_(1)cos2x+.^(n)C_(2)cos4x+.^(n)C_(3)cos 6x+"……")

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SOLUTION :L.H.S. `=(underset(r=0)overset(n)SUM.^(n)C_(r)sin2rx)/(underset(r=0)overset(n)sum.^(n)C_(r)cos2x)""(1)`
`0=(underset(r=0)overset(n)sum.^(n)C_(n-r)sin2(n-r)x)/(underset(r=0)overset(n)sum.^(n)C_(n-r)COS2(n-r)x)`
`=(underset(r=0)overset(n)sum.^(n)C_(r)sin(2n-2r)x)/(underset(r=0)overset(n)sum.^(n)C_(r)cos(2n-2r)x)""(2)`
`=(underset(r=0)overset(n)sum.^(n )C_(r)sin2rx+underset(r=0)overset(n)sum.^(n)C_(r)sin(2n-2r)x)/(underset(r=0)overset(n)sum.^(n)C_(r)cos2rx+underset(r=0)overset(n)sum.^(n)C_(r)cos(2n-2r)x)`.
(USING `a/b = c/d = (a+c)/(b+d)` and using (1) and (2))
`=(underset(r=0)overset(n)sum.^(n)C_(r)[sin2rx+sin(2n-2r)x])/(underset(r=0)overset(n)sum.^(n)C_(r)[cos2rx+cos(2n-2r)x])`
`= (2sin nx underset(r=0)overset(n)sum.^(n)C_(r)cos(2r-n)x)/(2cos nx underset(r=0)overset(n)sum.^(n)C_(r)cos(2r-n)x) = tan nx`
4602.

a, b, c are digits of a 3-digit number such that 64a + 8b + c = 403, then the value of a + b + c + 2013 is

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ANSWER :2024
4603.

Find the inverse of the following using elementary transformations. A=[[3,1],[5,2]]

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SOLUTION :`A^(-1) = [(2,-1),(-5,3)]`
4604.

Determine the truth of falsity of the"Every set has a proper subset" propositions with reasons.

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SOLUTION :EVERY set. has a PROPER SUBSET is false as `PHI` has no proper subset.
4605.

Evalute the following integrals int x^(3) e^(2x) dx

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Answer :`(E^(2x))/(16) [ (2x)^(3) - 3 (2x)^(2) + 6 (2x) - 6 ] + c `
4606.

Verify that the given function (explicit or implicit) isa solution of the correseponding differential equation :y = x^2 + 2x +c:y' - 2x - 2 = 0

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Solution :`y= x^2 + 2x + C`
`rArr y. = 2x + 2`
`rArr y. - 2x - 2 = 0`
`THEREFORE y = x^2 + 2x + c` is a solution of y. - 2x -2= 0
4607.

Verify that the given function (explicit or implicit) isa solution of the correseponding differential equation : y = e^x + 1: y'' - y' = 0

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SOLUTION :` y = e^x + 1`
`RARR y. = e^x`
`rArr y.. = e^x = y.`
`THEREFORE y.. - y. = 0 `
Therefore, `y = e^x + 1` is a solution of y.. - y. = 0
4608.

Verify that the given function (explicit or implicit) isa solution of the correseponding differential equation : y = sqrt(1 + x^2): y' = (xy)/(1 + x^2)

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SOLUTION :`y = sqrt(1 + x^2)`
`y.= 1/(2 sqrt(1+x^2)) (0+2x)`
`=x/sqrt(1+x^2) = (xsqrt(1+x^2))/(1+x^2) = (xy)/(1 + x^2) `
`THEREFORE y = sqrt(1 + x^2)` is a solution of `y. = (xy)/(1+x^2)`
4609.

Verify that the given function (explicit or implicit) isa solution of the correseponding differential equation : y = cos x + c: y' + sin x = 0

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SOLUTION :y = cos x + C
y. = -SIN x
`rArr y. + sin x = 0`
` THEREFORE` y = cos x + c is a solution of y. + sin x = 0
4610.

Derivative of e^(3 log x)w.r.t.x is 3x^2.

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ANSWER :T
4611.

If |z+i|^2-|z-i|^2=3then the locus of z is

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`4Y = 0`
`4y= 2`
`4y = 3`
`4y = 4`

ANSWER :C
4612.

The volume of a sphere is increasing at the rate of pi cm^(2)//sec. The rate at which the radius is increasing is ……….., when the radius is 3 cm.

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`(1)/(36)` cm/sec
36 cm/sec
9 cm/sec
27 cm/sec

Answer :A
4613.

The normal at a point P to the parabola y^(2) = 4x is parallel to the tangent at Q sqrt(2,2) to the hyperbola nd meets the axis of the parabola at If 5 is the focus of the parabola, area of the triangle PSR in sq. units is

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`9sqrt(2)`
`10sqrt(2)`
`18sqrt(2)`
`20sqrt(2)`

ANSWER :C
4614.

If A^T=[[-2,3],[1,2]] and B^T=[[-1,0],[1,2]] then find (A+2B)^T

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SOLUTION :we have `(A+2B)^T=A^T+(2B)^T=A^T+2B^T`
` B^T=[[-1,0],[0,2]] IMPLIES 2B^T=[[-2,0],[0,4]]`
THUS, `(A+2B)^T=A^T+2B^T=[[-4,5],[1,6]]`
4615.

C_0-2. C_1+3 . C_2 …..+ (-1)^n (n+1). C_n=

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`-1`
1
0
none

Answer :C
4616.

If a+b+c=0 and |a|=5, |b|=3 and |c|=7, then angle between a and b is

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`pi/2`
`pi/3`
`pi/4`
`pi/6`

Solution :Given, `|a|=5, |b|=3, |c|=7 and a+b+c=0`
`impliesa+b=-c`
On squaring both SIDES, we get
`(a+b)^(2)=(-c)^(2)IMPLIES|a+b|^(2)=|c|^(2)`
`implies|a|^(2)+|b|^(2)+2a*b=|c|^(2)`
`[because theta` be the ANGLE between a and b]
`implies(5)^(2)+(3)^(2)+2|a||b|cos theta =(7)^(2)`
`implies25+9+2.5.3cos theta =49`
`implies30 cos theta =15`
`implies cos theta =1/2=cos 60^(@)`
`impliestheta =(pi)/(3)`
4617.

If n is an integer other than a multiple of 3, then the value of 1 + omega^(n) + omega^(2n) is

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1
`-1`
0
3

Answer :C
4618.

If a times b=c" and "b times c=a, then

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a, B, c are orthogonal in PAIRS but `ABS(a) ne abs(c)`
a, b, c are orthogonal in pairs but `abs(b) ne 1`
a, b, c are not orthogonal to each other in pairs
a, b, c are orthogonal in pairs and `abs(a)=abs(c), abs(b)=1`

Answer :D
4619.

The sum of series Sigma_(n=1)^(oo) (2n)/(2n+1)! is

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E
`e^(-1)`
2E
`2e^(-1)`

ANSWER :B
4620.

Find the number of non negative integral solutions of x_(1)+x_(2)+x_(3)+x_(4)le20

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ANSWER :`""^(23)C_3-"^(14)C_3`
4621.

The value of x such that 3^(2x)-2(3^(x+2))+81=0 is

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`1`
`2`
`3`
`4`

ANSWER :B
4622.

The orthogonal trajectories of the family of curves a^(n-1)y=x^(n) are give by

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`X^(n)+n^(2)y=` constant
`NY^(2)+x^(2)=` constant
`n^(2)x+y^(n)=` constant
`n^(2)x-y^(n)=` constant

ANSWER :2
4623.

If x+iy=sqrt(phi+iy), where i=sqrt(-1)" and "phi and Psi are non-zero real parameters, then phi" and "Psi are constants, represents two system of rectangular hyperbola which intersect at an angle of :

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`(pi)/(6)`
`(pi)/(3)`
`(pi)/(4)`
`(pi)/(2)`

Answer :D
4624.

If ""^9P_5+"5 "^9P_4=^(10)P_r then find r

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ANSWER :5
4625.

If A is a skew Hermitian matrix then the main diagonal elements of A are all

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PURELY REAL
POSITIVE
NEGATIVE
purely imaginary

Answer :D
4626.

If the second and fifth terms of a G.P. are 24 and 3 respectively, then the sum of first six terms is

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181
`181/2`
189
`189/2`

ANSWER :D
4627.

If the circles x^2+y^2-2lambda x-2y-7=0 and 3(x^2+y^2)-8x+29y=0 are orthogonal then lambda=

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4
3
2
1

Answer :D
4628.

Differentiate the following w.r.t.x 2sin^-1x+tan^-1x+1

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SOLUTION :`d/dx(2sin^-1x+tan^-1x+1)=2XX1/(SQRT(1-x^2))+1/(1+x^2)+0=2/(sqrt1-x^2)+1/(1+x^2)`
4629.

If (1+x-2x^2)^8 = 1 + a_1x + a_2x^2 + ……+ a_16 x^16, then a_1 +a_3 + a_5 + ……+a_15 =

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`2^7`
`-2^7`
`3^2`
`4^6`

ANSWER :B
4630.

If z_1 & z_2 are two complex number & if arg (z_1+z_2)/(z_1-z_2)=pi/2 but |z_1+z_2|ne|z_1-z_2| thenthe figure formed by the points represented by 0, z_1, z_2 & z_1 + z_2is

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a parallelogram but not a rectangle or a RHOMBUS
a rectangle but not a square
a rhombus but not a square
a square

ANSWER :C
4631.

Find the equation of the circle whose diameter is the common chord of the circles x^2+y^2+2x+3y+1=0 and x^2+y^2+4x+3y+2=0

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ANSWER :`2(x^2+y^2)+2x+6y+1=0`
4632.

Evalute the following integrals int sqrt(1 + sec x )dx on ((2n - (1)/(2)) pi, (2n + (1)/(2)) pi, (n in z ))

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Answer :`- sin^(-1) X (2 COS x - 1) + C `
4633.

Area of the triangle with vertices (a, b ), (x_(1), y_(1)) and (x_(2), y_(2)), where a, x_(1), x_(2) are in G.P. with common ratio r and b, y_(1), y_(2) are in G.P. with common ratio s is :

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`AB(r-1) (s-1) (s-r)`
`(1)/(2) ab (r+1) (s+1) (s-r)`
`(1)/(2) ab (r-1)(s-1) (s-r)`
`ab(r+1)(s+1) (r-s)`

ANSWER :C
4634.

Let f (x,y) = (2xy)/(x ^(2)+2y ^(2)) (x,y) ne (0,0) =0 if (x,y) = (0,0) Show that f (x,y) is not continuous at (0,0) through continuous at all other points of R ^(2).

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ANSWER :`THEREFORE ` F is CONTINUOUS at `(0,0)`
4635.

Eleven apples are distributed between a girl and a boy.Then which one of the following statements is true?

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ATLEAST one of them will receive 7 apples.
The girl receives atleast 4 apples or the BOY receives at least 9 apples.
The girl receives atleast 5 apples or the boy receives atleast 8 apples
The girl receives atleast 4 apples or the boy receives atleast 8 apples.

Answer :D
4636.

Minimize and Maximize z=600x+400y Subject to the constraints : x+2y le 12 2x+y le 12 4x+5y ge 21 and xge0,y ge 0 graphical method.

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ANSWER :6
4637.

If a=sin(Cot^(-1)x)andb=cot(Sin^(-1)x) where xgt0, then 1//x^(2)-x^(2)=

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`B^(2)/a^(2)`
`a^(2)/b^(2)`
`(a^(2)+1)/(b^(2)-1)`
NONE of these

Answer :A
4638.

Evaluate the following definite integrals . int_(-1)^(1)e^(x)dx

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ANSWER :`e-1/e`
4639.

Lat l_(1)=int_(0)^(3)(sinx)/([(x)/(pi)]+(1)/(2))dx and l_(2)=int_(-3)^(0)(sinx)/([(x)/(pi)]+(1)/(2))dx, then (where[.] represent G.l.F.)

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`l_(2)+l_(2)=0`
`l_(2)=l_(2)`
`l_(1)=3l_(2)`
`l_(2)=3l_(1)`

Solution :`l_(1)=underset(0)OVERSET(3)(int)(sinx)/([(x)/(pi)]+(1)/(2))DX=underset(0)overset(3)(int)(sinx)/(0+(1)/(2))dx=underset(0)overset(3)(int)2sinx dx`
and `l_(2) =underset(-3)overset(0)(int)(sinx)/([(x)/(pi)]+(1)/(2))dx=underset(-3)overset(0)(int)(sinx)/(-1+(1)/(2))dx=underset(-3)overset(0)(int)-2sinx dx = underset(0)overset(3)(int)2sin x dx""thereforel_(1)=l_(2)`
4640.

If f is a continuous and differentiable funciton in x in (0, 1) such that Sigma_(r=0)^(10)(f(x+r)-|e^(x)-r-1|)=0, then int_(0)^(11)f(x)dx is

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`65+4ln 2 -7E`
`63+4ln 2-9e`
`69-9e`
`29-23e`

ANSWER :A
4641.

If S-= x^(2) + y^(2) + 2gx + 2fy + c= 0repre- sents a circle then show that the straight line lx + my + n = 0 (i) touches the circle S = 0 if (g^(2)+f^(2)-c) = ((gl+mf-n)^(2))/((l^(2)+m^(2)))

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ANSWER :`g^(2)+ f^(2) - C LT ((gl+mf-n)^(2))/((L^(2)+M^(2))
4642.

Delta=|{:(a_1,b_1,c_1),(a_2,b_2,c_2),(a_3,b_3,c_3):}|and Delta'|{:(A_1,B_1,C_1),(A_2,B_2,C_2),(A_3,B_3,C_3):}| where A_1,B_1,C_1,A_2,B_2,……… are respectively the cofactors of the elements a_1,b_1,c_1,a_2,b_2,….. of the determinant then Delta'=........

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0
`2DELTA`
`DELTA^3`
`Delta`

ANSWER :C
4643.

For eachof the following differential equations , determine its order , degree ( if exist ) ((d^(2)y)/(dx^(2))) + ((dy^(2))/(dx))^(2)= x sin ((d^(2)y)/(dx^(2)))

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ANSWER :the DEGREE is not DEFINED
4644.

int(dx)/((1+x)^(5)sqrt(x^2+2x))=(-1)/(8)(3theta-2sin2theta+(sin4theta)/(4))+C, where :

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`theta=sin^(-1)(x+1)`
`theta=sin^(-1)((1)/(1+x))`
`theta=2sin^(-1)((1)/(1+x))`
NONE of these

Answer :B
4645.

Iftheta is the angle between the pair of linesax^(2)+2hxy+by^(2)=0 then prove thatcostheta=(a+b)/(sqrt((a-b))+4h^(2))

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ANSWER :`(a+b)/(SQRT((a+b)^(2)+4H^(2)))`
4646.

The product of all nth roots of unity (n gt 1) is

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0
`(-1)^(n-1)`
-1
1

Answer :B
4647.

Integrate the following rational functions : int(5x)/((x+1)-(x^(2)+9))dx

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ANSWER :`-(1)/(2)log|X+1|+(1)/(4)log|x^(2)+9|+(3)/(2)tan^(-1)((x)/(3))+c`
4648.

Solution the differential equation (dy)/(dx) + 1 = e^(x+y) is

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`E^(-(x+y))+y = C`
`e^(x+y)+x+y = c`
`e^(-(x+y))+x+y = c`
`e^(-(x+y))+y + 2X = c`

ANSWER :C
4649.

If1 , omega , omega^(2)are the cube roots of unity prove that x^(2) + 4x + 7 = 0 " where " x = omega - omega^(2) - 2.

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4650.

Let three matrices A = [(-1,3,2),(2,-1,3),(1,2,3)], B = , C = [(-2,2,-1),(3,-5,4),(5,-6,4)] The value of log_(sqrt(8/7))[Tr^(2)(A) + +Tr^(3) ((ABC)/(2))+ Tr^(3) ((A(BC)^(2))/(2))+Tr^(3) ((A(BC)^(2))/(2))+.....+ oo] is [Note : Tr. (P) denote trace of matrix P] and Tr^(3)(A) = (Tr(A))^(3)

Answer»

`-4`
`2`
`6`
`4`

Solution :`BC = [(4,-2,3),(8,-3,5),(7,-2,4)][(-2,2,-1),(3,-5,4),(5,-6,4)] = I`
`TR(A) = -1 - 1 + 3 = 1`
`Tr((ABC)/2) = Tr(A/2) = 1/2`
`Tr^(2)(A) + +Tr^(3) ((ABC)/(2))+ Tr^(3) ((A(BC)^(2))/(2))+Tr^(3) ((A(BC)^(2))/(2))+.....+ oo`
`= 1^(3) + (1/2)^(3) + (1/4)^(3) + (1/8)^(3) + oo`
`= 1/(1 - 1/8) = 1/(7/8) = 8/7`.