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4701.

A: Ifthereare8 pointsin a planenothreeofwhichare onthe samestraight lineexcept4 pointsarecollinearthen thenumberofstraightlinesformedbyjoiningthemis 23. R :IF therearen pointsin a planenothreeof whichare onthe samestraightlineexceptp points are collinearthen thenumberof straightlinesformedbyjoiningthemis""^(n) C_2- ""^(p) C_2 +!.

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BothAand Raretrueand RIS thecorrectexplanationof A .
Both A ANDR aretruebutRisnotcorrectexaplanationof A
A istruebutR is FALSE
A is falsebutR is true

Answer :A
4702.

If veca is a nonzero vector of mangitude 'a' and lambda a nonzero scalar , then lambdaveca is unit vector if

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`lambda=1`
`lambda=-1`
`a=|lambda|`
`a=1//|lambda|`

ANSWER :D
4703.

Order of the differential equation of the family of all concentric circles centered at (h,k) is

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1
2
3
4

Answer :A
4704.

Match the following:

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<P>

Answer :`(A)(s)(B)(r)(C)(Q)(D)(p)`
4705.

Match the following:

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ANSWER :(A)(p)(B)(Q)(C)(R)(D)(s)`
4706.

Find the point of intersection of the circle x^(2)+y^(2)+4x+6y-39=0 and the normal at (2,3).

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ANSWER :(-6,-9)
4707.

Prove that the point (-1, -2) lies on the circle x^(2) + y^(2) - x y - 8 = 0. Find the coordinates of the other extremity of the diameter through (-1, -2).

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ANSWER :(2, 3)
4708.

Let a,b,c are positive real numbers such that p =a ^(2) b + ab ^(2) c - ac ^(2), q =b ^(2) c+bc^(2) -a ^(2)b-ab ^(2) and r =ac ^(2) +a^(2) c - cb^(2) - bc ^(2) and the quadratic equation px ^(2) +qx+r=0 has equal roots , then a,b,c are in :

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A.P.
G.P.
H.P.
None of these

ANSWER :C
4709.

If x,y,z are nonzero real numbers, then the inverse of matrix A=[{:(x,0,0),(0,y,0),(0,0,z):}] is ………

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`[{:(x^(-1),0,0),(0,y^(-1),0),(0,0,z^(-1)):}]`
`XYZ[{:(x^(-1),0,0),(0,y^(-1),0),(0,0,z^(-1)):}]`
`1/(xyz)[{:(x,0,0),(0,1,0),(0,0,1):}]`
`1/(xyz)[{:(1,0,0),(0,1,0),(0,0,1):}]`

ANSWER :A
4710.

Given that lim_(nrarroo) sum_(r=1)^(n) (log_(e)(n^(2)+r^(2))-2log_(e)n)/n = log_(e)2+pi/2-2, then evaluate :lim_(nrarroo) (1)/(n^(2m))[(n^(2)+1^(2))^(m)(n^(2)+2^(2))^(m) "......"(2n^(2))^(m)]^(1//n).

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SOLUTION :N//A
4711.

Prove that the sum of all the vectors drawn from the centre of a regular octagon to its vertices is the null vector.

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Solution :
Let O be the centre of a regular OCTAGON ABCDEFGH.
Then `vec(OA)` = `-vec(OE)`, `vec(OB)` = `-vec(OF)`
`vec(OC)` = `-vec(OG)`, `vec(OD)` = `-vec(OH)`
Now `vec(OA)+vec(OB)+vec(OC)+vec(OD)+vec(OE)+vec(OF)+vec(OG)+vec(OH)`
=`(vec(OA)+vec(OE)) + (vec(OB)+vec(OF)) + (vec(OC)+vec(OG)) + (vec(OD)+vec(OH))`
= `vec0+vec0+vec0+vec0` = 0
4712.

Find the number of proper divisors of 2520. How many of them are divisible by 10. Find their sum.

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ANSWER :4760
4713.

If AB=0 for the matrices

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an ODD MULTIPLE of `(PI)/(2)`
an odd multiple of `pi`
an EVEN multiple of `(pi)/(2)`
0

Answer :A
4714.

Find the value of b for which difference between maximum and minimum value of x^2 - 2bx - 1 in [0, 1] is 1.

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ANSWER :b=0
4715.

Consider a set of point Rin which is at a distance of 2 units from the line (x)/(1)= (y-1)/(-1)= (z+2)/(2) between the planes x-y+2z=3=0 and x-y+2z-2=0.

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The volume of the bounded figure by POINTS R and the planes is `(10//3sqrt3)pi` cube units.
The AREA of the curved surface formed bythe set of points R is `(20 pi //sqrt6)` sq.units.
The volume of the bounded figure by the set of points R and the planes is `(20pi//sqrt6)` cubic units.
The area of the curved surface formedby the set of points R is `(10//sqrt3)pi` sq. units.

Solution :Distance between the planes is `h= 5//sqrt6`.
ALSO the figure formed is a CYLINDER, whose radius is `r=2` units.
Hence, the volume of the cylinder is
`""pir^(2)h= pi(2)^(2)*(5)/(sqrt6)= (20pi)/(sqrt6)` cubic units.
Also the curved surface area is
`""2pirh= 2pi(2)*(5)/(sqrt(6))= (20pi)/(sqrt6)`
4716.

If x=a cos ^(3) theta and y = a sin^(3) thetathen (dy)/( dx) =

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ANSWER :`(DY)/( DX) = ROOT(-3) (y/x)`
4717.

the ( relative) minimumvalue of( x^2- 3x +2) /(x^2+ 3x+2)is

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`-1//11`
`-17+12sqrt(2)`
`-17-12 SQRT(2)`
0

Answer :B
4718.

Prove that the sum of two functions increasing on a certain open interval is a function monotonically increasing on this interval. Will the difference of increasing functions be a monotomic function?s

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ANSWER :`[1/2, OO)`
4719.

Show that the equaton of any circle in the complex plane is of the form z barz+b bar z+ b bar z+c=0,( b in C, c in R)

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Solution :Assume the genral FRORM of the equation of a circle in cartesion co-ordinates as
`x^(2)+y^(2)2ag+2fy+c=0`
`(g , f in R)""..(1)`
To write this equation in the complex VARIABLE formlet `(x,y)=Z`
Then `(z+ BAR z)/(2)= x, (z- bar z)/(2 i)`
`=y=(-i (z bar z))/(2)`
`:.x^(2)+y^(2)=|z|^(2)=z barz`
Substituting these,RESULTING in equation (1), we obtain
`z bar z+g(z+barz)+f(z- barz)(-i)+c=0`
i.e., `z bar z+(g- if)z+ (g+ if) bar z+c=0 "" (2)`
If `(g+if)=b` , then equation (2) can be writenas `z bar z+ bar b z+b bar z+c=0`
4720.

"^(30)C_(0)*^(20)C_(10)+^(31)C_(1)*^(19)C_(10)+^(32)C_(2)*18C_(10)+....^(40)C_(10)*^(10)C_(10) is equal to

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`"^(51)C_(41)`
`"^(50)C_(40)`
`"^(51)C_(21)`
`"^(50)C_(40)`

Solution :`(a)` `'^(30)C_(0)*^(20)C_(10)+^(31)C_(1)*^(19)C_(10)+^(32)C_(2)*^(18)C_(10)+....^(40)C_(2)*^(10)C_(10)`
`="coefficient of " x^(10) " in" (1-x)^(-11)(1-x)^(-31)`
`="coefficient of " x^(10) " in" (1-x)^(-42)`
`='^(42+10-1)C_(42-1)=^(51)C_(41)=^(51)C_(10)`
4721.

If (y)/(3)=6x, then in terms of y, which of the following is equivalent to x?

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`2Y`
`y`
`(y)/(2)`
`(y)/(18)`

ANSWER :D
4722.

If P(A)=0.7, P(B)=0.4 then the interval in which P(AnnB) lies is

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`[0.1,0.4]`
`[0.1,0.6]`
`[0,04]`
`[0,0.8]`

ANSWER :A
4723.

Explain why the experiment of tossing a coin three times is said to have binomial distribution.

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ANSWER :TOSSING COINE 3 TIMES.
4724.

If A is a 2xx2 matrix such that

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`A^(2008+I)`
`A^(2009+I)`
A+I
A

Answer :C
4725.

int secx log (sec x+ tan x)dx=

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ANSWER :`(1)/(2)(log|secx+tanx|)^(2)+C`
4726.

Find the transformed equation of x^(2)+2sqrt3 xy-y^(2) = 2a^(2) when the axes are rotated through an angle 30^(0).

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ANSWER :`X^2-Y^2=a^2`.
4727.

Evalute the following integrals int ((x +1)(x + "log x")^(2))/(x )dx

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ANSWER :` - (1)/(3) log | 2 - 3 " log x"| + C `
4728.

If |{:(a,b,ax+by),(b,c,bx+cy),(ax+by,bx+cy,0):}|=0 and ax^2+2abxy+cy^2ne0," then "......

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a,B,C are in A.P
a,b,c are in G.P
a,b,c are A.P and G.P both
a,b,c are NEITHER in A.P nor in G.P

Answer :B
4729.

Find all polynomials whose coefficients are equal to 1 or - 1 and whose all roots are real.

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ANSWER :`+-(X^(3) +x^(2)-x+1)`
4730.

If the coefficients of r^(th), (r+1)^(th) " and "(r+2)^(th) terms in the expansion of (1+x)^(14) are in an arithmetic progression, then r =

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4 or 10
5 or 9
8 or 6
7

Answer :B
4731.

A bag contains 6 white balls and 4 black balls. A ball is drawn and is put back in the bag with 5 balls of the same colour as that of the ball drawn. A ball is drawn again at random. What is the probability that the ball drawn now is white.

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ANSWER :`(3)/(5)`
4732.

If x^3 -3x^2 + 4=0 hasa multiplerootthenthatmultipleroot is

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0
2
1
3

Answer :B
4733.

f: R rarr R , f(x) ={{:(-1,xlt0,),(0,x=0 , g:R rarr R ","g(x)=),(1,xgt0,):} 1 + x - [x] then for all x, f (g(x)) = ........

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1
2
0
`-1`

SOLUTION :N/A
4734.

Using Rolle's theroem, find the point on the curve y = x (x-4), xin [0,4], where the tangent is parallelto X-axis.

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Solution :We have, `y = x(x-4),x in [0,4]`
(i) y is a continuous function since`x(x-4)` is a polynomialfunction.
Hence, ` y = x (x-4)` iscontinuousin `[0,4]`.
(ii) `y'= (x-4).1+x.1=2x-4` which existsin `(0,4)`.
Hence, `y` is differentiablein `(0,4)`.
(iii) `y(0) = 0(0-4) = 0`
and `y(4) = 4(4-4) = 0`
` rArr y(0) =y(4)`
Since,conditions of Rolle's theorem are satisfied.
Hence, there exists a POINT such that
`f(c) = 0` in `(0,4), [:' f(x) = y']`
`rArr 2c - 4 = 0`
`rArr c = 2`
`rArr x =2, y = 2(2-4) = - 4`
THUS, `(2,-4)`is the pointon the curve at which thetangent drawnis parallel to X-axis.
4735.

Solve for x and y : x[{:(2),(1):}]+y[{:(3),(5):}]+[{:(-8),(-11):}]=[{:(0),(0):}]

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ANSWER :`=2`
4736.

int(1)/(root(n)((x-a)^(n-k)(x-b)^(n+k))) ("Hint put"(x-a)/(a-b)=t)

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ANSWER :`(1)/(a-b)(N)/(K)((x-a)/(x-b))^(k//n)+C`
4737.

int(dx)/(xsqrt(ax+b))

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4738.

int(cos^(3)x)/(sinx)dx

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4739.

If z is a complex number satisfying |z|^(2)+2(z+2)+3i(z-barz)+4 =0, then complex number z+3+2i lies on

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circle witih center 1-5i and radius 4
circle with center 1+5i and radius 4
circle with center 1+5i and radius 3
circle with center 1-5i and radius 3

Solution :We have,
`|z|^(2)+2(z+barz)+3i(z-barz)+4=0`
`RARR zbarz+(2+3i)z+(2-3i)barz+4=0`
CLEARLY, it REPRESENTS a circle with centers as `(-2,3)` and radius `=sqrt(4+9-4)=3`.
The above equation can be written as
`|z-(2+3i)|=4` or , `|z+2-3i|=4 rArr |omega-3-2i+2-3i|=4 rArr |omega-1-5i|=4`
`rArr omega` lies on the circle with center 1+5i and radius 4.
4740.

If bara,barb barc and bard are non-zero, non-collinear vectors such that bard is perpendicular to bara,barb and barc and (bara.barc)bara=barc then bara.(barb times bard) is equal to

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`(barc.bard)/|barc|^2`
`|barc|^2`
`(bara.bard|)/|bara|^2`
NONE of these

Answer :D
4741.

If x_(1), x_(2)=3, x_(3)+x_(4)=12 and x_(1), x_(2), x_(3), x_(4) are in increasing G.P then the equation having x_(1), x_(2) as roots is

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`X^(2)-3x+2=0`
`x^(2)- 6x+8=0`
`x^(2)-12x+32=0`
`x^(2)-9x+8=0`

ANSWER :A
4742.

overset(pi)underset(0)int (x)/(1+sinx)dx

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ANSWER :`:. I=pi`
4743.

lim_(xto0)(log(1+3x^(2)))/(x(e^(5x)-1))=

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`3/5`
`5/3`
`(-3)/(5)`
`(-5)/(3)`

ANSWER :A
4744.

A shopkeeper sells three types of flower seeds A_(1), A_(2), and A_(3). They are sold as a mixture, where the proportions are 4:4:2 respectively. The germination rates of the three type ofseeds are 45%, 60% and 35%. Calculate the probability (i) Of a randomly chosen seed to germinate (ii) That it will not germinate given that the seed is of type A_(3). (iii) That it is of the type A_(2) given that a randomly chosen seed does not germinate.

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ANSWER :(i) 0.49, (II) 0.65, (III) 0.314
4745.

Provethe followinginequalities. (i) x gt tan^(-1) (x) """for """x in (0,oo) (ii) e^(x) gt x+1 """ for""" x in (0,oo) (iii) (x)/(1+x) le en (1+x) le x"""for """ x in (0,oo)

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4746.

A vector of magnitude sqrt2 coplanar with hati+hatj+2hati and hati+2hatj+hatk and perpendicular to hati+hatj+hatk is

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`-hatj+hatk`
`hati-hatk`
`hati-hatj`
`hati-2hatj+hatk`

SOLUTION :A vector COPLANAR with `hat(i)+hat(J)+2hat(K)` and `hat(i)+2hat(j)+hat(k)` is
`hat(i)+hat(j)+2hat(k)+lambda(hat(i)+2hat(j)+hat(k))=(1+lambda)hat(i)+(1+2 lambda)hat(j)+(2+lambda)hat(k)`
it is perpendicular to `hat(i)+hat(j)+hat(k)`
`:. 1+lambda+1+2 lambda+2+lambda =0""[ :' a.b=0]`
`implies lambda=-1`
`:.` Required vector is `-hat(j)-hat(k)`.
4747.

Integrate the following inta^(2x)dx

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SOLUTION :`inta^(2X)dx
[put 2x=t then 2sx=dt or dx=(1/2)dt]
`inta^tcdot(1/2)dt=(1/2)inta^tdt`
`a^(2x)/(2Ina)+C`
4748.

Find the number of all onto functions from the set {1,2,3,.......,n} to itself.

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SOLUTION :N/A
4749.

If x=ct and y= (c )/(t), find (dy)/(dx) at t=2

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a. 0
b. `(-1)/(4)`
c. 4
d.`(1)/(4)`

Answer :B
4750.

If y = (log)^(cos x) find (dy)/(dx).

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ANSWER :`(LOG X)^(COS x) [(cos x)/(x log x)-SIN x log(log x)]`