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7501.

Prove that |{:(x^2,y^2,z^2),((x+1)^2,(y+1)^2,(z+1)^2),((x-1)^2,(y-1)^2,(z-1)^2):}|=-4(x-y)(y-z)(z-x)

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ANSWER :`4(x-y)(y-z)(z-x)`
7502.

Provethat the sum of eccentric angles of four concylic points on the ellipse(x^(2))/(a^(2))+(y^(2))/(b^(2))=1 is 2npi, wheren in Z

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Solution :Let the CIRCLE `x^(2)+y^(2)+2gx+2fy+e-0` CUT the ellipse `(x^(2))/(a^(2))+(y^(2))/(b^(2))=1` in four ponts , P,Q,R and S.
Solving circle and ellipse `(x=a cos theta, y=b sin theta)`, we have `a^(2)cos^(2)theta+b^(2)theta+2agcos theta+2bf sin theta+c=0`
`rArra^(2)((1-t^(2))/(1+t))+b^(2)((2t)/(1+r^(2)))^(2)+2ag((1-r^(2))/(1+t^(2)))+2bf((2t)/(1+t))+c=0"where"t=tan.(theta)/(2)`
`rArra^(2)(1-r^(2))^(2)+4b^(2)t^(2)+2ag(1-t^(2))^(2)(1-t^(2))+4bft(1+f^(2))+c(1+r^(2))^(2)=0`
`rArr(a^(2)-2ag+c)t^(4)+4bft^(3)+(-2a^(2)+4b^(2)+2c)t^(2)+4bft+(a^(2)+2ag+c)-0`
Roots of equation are `tan.(alpha)/(2),tan.(beta)/(2),tan.(gamma)/(2) and tan. (delta)/(2)`, where `alpha,beta,gamma and delta` ECCENTRIC angles of P,Q,R and S respectively .
Now,`tan ((alpha)/(2)+(beta)/(2)+(gamma)/(2)+(delta)/(2))=(s_(1)-s_(2))/(1-s_(2)+s_(4))`
Wherem `s_(i)` = sum of products of tangents of HALF angles taken 'i' at a time
CLEARLY, from eqution (1),
`s_(1)=s_(3)=(-4bf)/(a^(2)-2ag+c)`
`tan ((alpha)/(2)+(beta)/(2)+(gamma)/(2)+(delta)/(2))=0`
`rArr(alpha+beta+gamma+delta)/(2)=npi,n in Z`
`rArr alpha+beta+gamma+delta=2npi,n in Z`
7503.

If alpha,beta,gammaare the roots of p x^2+q x^2+r=0,then the value of the determinant |alphabetabetagammagammaalphabetagammagammaalphaalphabetagammaalphaalphabetabetagamma|ispb. qc. 0d. r

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pq
qr
0
pr

Answer :C
7504.

The value of the expression 2^(k)((n),(0))((n),(k))-2^(k-1)((n),(1))((n-1),(k-1))+2^(k-2)((n),(2))((n-2),(k-2))….+(-1)^(k)((n),(k))((n-k),(0)) i

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`((N),(K))`
`((n+1)/(k))`
`((n+1),(k+1))`
`((n-1),(k-1))`

ANSWER :A
7505.

If a normal chord at a point t on the parabola y^(2)=4ax subtends a right angle at the vertex, then t equals to

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1
`SQRT2`
2
`sqrt3`

Answer :B
7506.

The value of sin^(-1)(cos""(53pi)/(5)) is

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a.`(3PI)/(5)`
b.`(-3pi)/(5)`
c`(pi)/(10)`
d.`(-pi)/(10)`

ANSWER :D
7507.

The standard deviation of 50 values of a vartiable x is 15 is each value of the vartiable is divided by (-3), then the standard deviation of the new set of 50 values of x will be-

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15
`-5`
5
`-15`

ANSWER :C
7508.

An insurance company insured 2000 scooter drivers. 4000, car drivers and 6000 truck driver. The probability of an accident involving a scooter, a car and a truck is 1/00,3/100and 3/20 respectively. One of the insured persons meets with an accident. What is the probability that he is a scooter driver ?

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SOLUTION :Total number of persons insured `=(2000+4000+6000)=12000`.
Let `E_1,E_2andE-3` be the events of choosing a scooter driver, a car driver and truck driver respectively. Then,
`P(E_1)=2000/12000=1/6,P(E_2)=4000/12000=1/3andP(E_3)=6000/12000=1/2`.
Let E be the event of an insured PERSON meeting with an accident.
Then ,
`P(E//E_1)` = probability that an insured person meets with an accident, given that he is a scooter driver
`=1/100`
Similarly, `P(E//E_2)=3/100andP(E//E_3)=3/20`.
REQUIRED probability
`=P(E_1//E)` [by BAYES's theorem]
= probability of choosing a scooter driver, given that he meets with an accident
`=(P(E//E_1).P(E_1))/(P(E//E_1).P(E_1)+P(E//E_2).P(E_2)+P(E//E_3).P(E_3))`
`=((1/100xx1/6))/((1/100xx1/6)+(3/100xx1/3)+(3/20xx1/2))=1/52`.
Hence, the required probability is `1/52`.
7509.

l=int(sin2x)/(8sin^(2)x+17cos^(2)x)dx is equal to

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`-(1)/(9)log_(E)(8sin^(2)x+17cos^(2)x)+c`
`log_(e)""(1)/(ROOT(9)(8+9cos^(2)x))+c`
`log_(e)""(1)/(root(9)(17-9sin^(2)x))+c`
none of these

Answer :A::B::C
7510.

If A, B, C are angles of a triangle ABC, then |(sin.(A)/(2),sin.(B)/(2),sin.(C)/(2)),(sin(A+B+C),sin.(B)/(2),sin.(A)/(2)),(cos.((A+B+C))/(2),tan(A+B+C),sin.(C)/(2))| is less than or equal to

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`(3sqrt(3))/(8)`
`(1)/(8)`
`2sqrt(2)`
2

Answer :B
7511.

If G(g), H(h) and P(p) are centroid' orthocentre and circumcentre of a triangle and x p+y h+z g=0, then (x, y, z) is equal to

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1, 1, -2
2, 1, -3
1, 3, -4
2, 3, -5

Solution :We know that, orthocentre, entroid and circumentre of a triangle are COLLINEAR and CENTROID DIVIDES orthocentre and cicumcentre in the ratio `2:1`

By USING internally division,
`(2p+1h)/(2+1)=g implies2p+h-3g=0`
But it is given, ` xp+yh+zg=0`
`thereforex=2, y=1 and z=-3`
7512.

Ifthe angles of a triangle ABC satisfy the equation 81^(sin^(2)x)+81^(cos^(2)x)=30, then the triangle can not be

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equilateral
isosceles
obtuse angled
right angled

Answer :d
7513.

int (1)/(4 + 5 cos 2 theta) d theta =

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`(1)/(6) LOG |(3 + tan theta)/(5 - tan theta)| + C `
`(1)/(3) log |(2 + tan theta)/(3- tan theta)| + c `
`(1)/(6) log |(3 + tan theta)/(3 - tan theta)| + c `
`(1)/(2) log |(3 + tan theta)/(3 - tan theta)| + c `

ANSWER :C
7514.

Let F(x)= f(x) + f(1/x), where f(x)= int_(1)^(x) (ln t)/(1+t)dt, then F(e)=

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2
`1//2`
0
1

Answer :B
7515.

A and B toss a fair coin 50 times each simultaneously. Then find the probability that both of them will not get tails at thesame toss

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ANSWER :`((3)/(4))^(50)`
7516.

Let f(x)=x^(2)+ax+b be a quadratic polynomial in which a and b are integers. If for a given integer n, f(n) f(n+1)=f(m) for some integer m, then the value of m is

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`N(a+b)+AB`
`n^(2)+an+b`
`n(n+1)+an+b`
`n^(2)n+a+b`

ANSWER :C
7517.

Prove that (1)/(log_(sqrt(bc))(abc))+(1)/(log_(sqrt(ca))(abc))+(1)/(log_(sqrt(ab))(abc))=1 (ii)(log_(2)10)(log_(2)80)-(log_(2)5)(log_(2)160)=4 (iii) a^(sqrt(log_(a)b))=b^(sqrt(log_(b)a)) (iv) (a^(log_(2^(1//4))2)-3^(log_(27)(a^(2)+1)^(3))-2a)/((7^(4log_(49)a))-a-1)=a^(2)+a+1

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7518.

int _(a) ^(b) (dx)/( sqrt(1 + x ^(2))) where a = (e-e^(-1))/( 2 ) &b = (e ^(2) -e ^(-2))/(2 )

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ANSWER :1
7519.

Iftheta _ 1 and theta _2are the angles of inclination of tangents through a point P to the circlesx^(2) + y^(2)=a^(2),then find the locus of Pwhencot theta _1 + cot theta _1 =k

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<P>

Answer :` THEREFORE ` The locus of p ` (x_1,y_1)is k(y^(2) - a^(2))=2XY `
7520.

Differentiate the following w.r.t.x e^(x^2)

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SOLUTION :`d/dx(E^(x^2))=e^(x^2)d/dx(x^3)=e^(x^2)(3x^2)=3x^2e^(x^2)`
7521.

If A and B are independent events,show that A^c and B are independent.

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SOLUTION :P`(A^c CUP B)`=P(B-A)
=P(B)-P(A capB)`thereforeA^c` and B are independent EVENTS.
7522.

If|x|isso small thatx ^ 2andhigherpower ofx maybeneglectedthenan approximatevalue of((1 + (2 )/(3)x) ^(-3) (1 - 15 x ) ^(-1//5))/((2- 3x ) ^ 4)is

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` (1 )/(8) (1+ 7x ) `
` (1 )/(16) (1 - 7x ) `
`1-7x `
`( 1 )/(16) (1 + 7x ) `

Solution : ` (( 1 +(2 ) /(3)x )^( -3) (1 -15 x ) ^(-1/5))/((2 - 3X ) ^(4 ))`
`=(1 + (2 ) /(3) x ) ^(-3)( 1- 15x ) ^(-1/5) ( 2 - 3 x ) ^(-4 ) `
`= (1+(2)/(3) x ) ^(-3)( 1-15x ) ^( - 1/5 )2^(- 4 )( 1-(3x ) /(2) ) ^( - 4 ) `
NEGLECTING`x ^ 2`andhigherpowersof` .x.`
`= (1)/(16)(1- 3((2)/(3)) x)(1- 15x(-1/5)) ( 1 +(3x ) /(2)(4)) `
`= (1 ) /(16)(1 - 2X ) (1 + 3x )( 1 +6x )`
`= (1 ) /(16) (1 + x )(1 + 6x ) `
Neglecting`x ^ 2`andhigherpowersof `.x.`
`=(1)/(16)( 1 +7x)`
7523.

Consider the polynomialf(x)=1 + 2x + 3x^2 +4x^3for all x in R

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`(-1//4,0)`
`(-11 ,-3 //4)`
`(-3 //4, -1//2)`
`(0 ,1//4)`

Solution :We have
`f(x)=1+2x+3x^2+4x^2`
`rArr f(x)=2+6x+12x^2=2(6x^2+3x+1) gt 0` for all `x in R`
`rArrf(x)` is striclly increasing on R
Now `f(-3//4) lt 0` and `f(-1//2) gt 0`
`rArr ` f(x) has a REAL root between `-3/4 " and" -1/2`
ALSO f(x) is stricly increasing on R. So f(x) has exactly one real root in the interval `(-3/4, -1/2)`
7524.

Find the number of proper divisors of lfloor15

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ANSWER :4030
7525.

Corresponding to a triangle ABC, match the items given in List-I with the items given in List II. {:(,"List I",,"List II"),((A),rr_(2)=r_(1)r_(3),(I),angleA=90^(@)),((B),r_(1)+r_(2)=r_(3)-r,(II),b^(2)=c^(2)+a^(2)),((C),r_(1)=r+2R,(III),angleC=90^(@)),(,,(IV),angleB=120^(@)):} The correct match is

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`{:(A,B,C),(II,III,I):}`
`{:(A,B,C),(II,I,III):}`
`{:(A,B,C),(I,IV,II):}`
`{:(A,B,C),(III,I,IV):}`

ANSWER :A
7526.

If a hyperbola has one focus at the origin and its eccentricity is sqrt2 .One of the directrices isx+y+1=0 . Then the centre of the hyperbola is

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`(-1,1) `
`(1,-1)`
` ( -2,-1) `
` ( 2,2) `

ANSWER :A
7527.

Find the projection of the point (7,-5,3) on y-axis

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SOLUTION :(0,-5,0),
7528.

Multiply (3sqrt(-7)-5sqrt(-2))(3sqrt(-2)+5sqrt(-2)

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SOLUTION : `(3sqrt(-7)-5sqrt(-2))(3sqrt(-2)+5sqrt(-2)`
`=3sqrt(7I)-5sqrt(-2i)(3sqrt(2i)+5sqrt(2i)`
`=i^2(3sqrt7-5sqrt2)(3sqrt2+5sqrt2)`
`=(-1)8sqrt2(3sqrt7-5sqrt2)=-24sqrt(14)+80`
7529.

Which of the following options is the only CORRECT combination ?

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<P>(I) (II) (S)
(I) (iii) (P)
(I) (iii) (Q)
(I) (ii) (Q)

Answer :C
7530.

Which of the following options is the only CORRECT combination ?

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<P>(II) (ii) (P)
(II) (i) (R)
(II)(i) (S)
(II) (IV) (R)

ANSWER :B
7531.

Using differentiable, find the approximate value of each of the following upto 3 places of decimal.sqrt49.5

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SOLUTION :`sqrt49.5=7.035`
7532.

Which of the following options is the only CORRECT combination ?

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<P>(III) (II) (S)
(III) (iii) (R)
(III) (i) (P)
(III) (ii) (P)

ANSWER :D
7533.

If f(x)={{:((sqrt(1+px)-sqrt(1-px))/(x)",",-1lexlt0),((2x+1)/(x-2)",",0lexle1):} continauous on [ -1,1], then p =

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`-1/2`
`-1/4`
`1/2`
`2`

ANSWER :A
7534.

The normal to the circle given by x^2+y^2-6x+8y-144=0 at (8,0) meets the circle again at the point

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`(2,-16)`
`(2,16)`
`(-2,16)`
`(-2,-16)`

ANSWER :D
7535.

A plane passes through (2,3,-1) and is perpendicularto the line having direction ratios 3,-4,7 . The perpendicular distance from the origin to this planeis

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`3/(SQRT(74))`
`5/(sqrt(74))`
`6/(sqrt(74))`
`13/(sqrt(74))`

ANSWER :D
7536.

For the straightlines 2x - y + 1 = 0 and x - 2y - 2 = 0 find the equation of the (i) bisector of the obtuse angle between them , (ii) bisector of the acute angle between them ,

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Answer :`x + y + 3 = 0, 3X - 2Y = 1`
7537.

Show that the points (1,1),(-1,-1) and (-sqrt3,sqrt3) are the vertices of an equilateral triangle.

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Solution :
`THEREFORE absbar(AB) = sqrt((-1-1)^2 + (-1-1)^2) = 2sqrt2` Slope of
`absbar(BC) sqrt((-1+sqrt3)^2 + (-1-sqrt3)^2)`
= `sqrt(2)(1+3) = 2sqrt2`
`absbar(AC) = sqrt((1+sqrt3)^2 + (1-sqrt3)^2)`
= sqrt(2)(1+3) = 2sqrt2`
`therefore BARAB = barBC = barAC`
`therefore` ABC is an equilateral TRIANGLE.
7538.

Two dice are thrown simultaneously. The probability of obtaining a total score of 5 is

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`(1)/(18)`
`(1)/(12)`
`(1)/(9)`
`(1)/(6)`

Answer :C
7539.

Statement-1: int_(0)^(pi//2) x cot x dx=(pi)/(2)log2 Statement-2: int_(0)^(pi//2) log sin x dx=-(pi)/(2)log2

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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 not a correct explanation for Statement-1.
Statement-1 is True, Statement-2 is False.
Statement-1 is False, Statement-2 is True.

Solution :Clearly, statement-2 is true. (SEE an important RESULT on page 44.16)
Now, `underset(0)overset(pi//2)int X cot x dx=[x log sin x]_(0)^(x//2)-underset(0)overset(pi//2)int log sin x dx`
`rArr underset(0)overset(pi//2)int x cot x dx=0underset(x to 0)LIM x logsin x-(-(pi)/(2)log2)`[Using Statement-2]
`rArr underset(0)overset(pi//2)int x cot x dx=(pi)/(2)log 2`
So, statement-1 is true. Also,Statement-2 is a correct explanation for statement.
7540.

If A and B are matrices of order 3 and |A| = 5 , |B| = 3, then |3AB| = 27xx5xx3=405.

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ANSWER :TRUE
7541.

int "sec"^(2) (7 - 4x) dx.

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ANSWER :`-1/4tan(7-4x)+C`
7542.

(sin (log i^(i)))^3 + (cos (log i^(i)))^3 =

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`0`
`-1`
`1`
`(PI)/(2)`

ANSWER :B
7543.

Positive Integer just greater than (1+0.0001)^(10000) is :

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2
3
4
None of these

Solution :`(1+0.0001)^(10000)=(1+(1)/(10000))^(10000)`
now we know that
`2le (1+(1)/(n))^(n)lt 3, n GE 1, n in N`
HENCE POSITIVE Integer just greater that `(1+0.0001)^(1000)` is 3.
7544.

Ifveca=hati-hatk,vecb=xhati+hatj+(1-x)hatk,vecc=yhati+xhatj+(1+x-y)hatkshow that[veca,vecb,vecc]depends on neither .x nor y.

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onlyx
onlyy
Neither X or y
Both x and y

Answer :C
7545.

Let A be the event of having 53 sundays and B be the event of having 53 Mondays in a leap year. Decide whether A, B are independent or not.

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ANSWER :No
7546.

For the reaction CH_(3)COCH_(3)+Br_(2)overset(H^(+))toCH_(3)COCH_(2)Br+H^(+)+Br^(-) the following data was collected {:(["Acctone"],[Br_(2)],[H^(+)],"Rate of reaction "(Ms^(-1)),),(" "0.15,0.025,0.025," "6xx10^(-4),),(" "0.15,0.050,0.025," "6xx10^(-4),),(" "0.15,0.025,0.050," "12xx10^(-4),),(" "0.20,0.025,0.025," "8.0xx10^(-4),):} Calculate order of the reaction w.r.t. CH_(3)COCH_(3)andBr_(2)

Answer»

Solution :`"RATE"=k."[ACETONE]"^(x).[Br_(2)]^(y).[H]^(z)` <BR> `6xx10^(-4)=k.(0.15)^(x)(0.025)^(y)(0.025)^(z)`. . . .(i)
`6xx10^(-4)=k.(0.15)^(x)(0.050)^(y)(0.025)^(z)`. . . .(ii)
`12xx10^(-4)=k.(0.15)^(x)(0.025)^(y)(0.050)^(z)`. . . .(iii)
`8xx10^(-4)=k.(0.20)^(x)(0.025)^(y)(0.025)^(z)`. . . .(iv)
(i) `divide` (ii), `1((0.025)/(0.050))^(y)`
y=0, hance rate does not depend upon the CONCENTRATION of `Br_(2)`.
(i) `divide` (iii), `(6)/(12)=((0.025)/(0.050))^(z),(1)/(2)=((1)/(2))^(z)`
`:.z=1`
(i) `divide` (iv), `(3)/(4)=((3)/(4))^(x)`
`:.x=1""]`
7547.

Integrate the following intdx/(sqrt(1-(x-1)^2)

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SOLUTION :`(int(DX)/(sqrt(1-(x-1)^2))`
put x-1=t then dx=dt
`dt/(sqrt(1-t^2)=sin^(-1)t+C`
7548.

LetA ={ 1,2,3,4,5}and Rbe therelationon AdefinedbyR= {(a,b}: b=a^2} writeRin rosterform

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ANSWER :`R={1,4}`
7549.

Write the sum of the order and degree of the differential equation : d/(dx){((dy)/(dx))^4}=0

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ANSWER :3
7550.

bar(a),bar(b) and bar( c ) are three unit vectors. bar(a)_|_bar(b) and bar(a)||bar( c ) then bar(a)xx(bar(b)xx bar( c )) = …………….

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`BAR(a)`
`bar(B)`
`bar( C )`
0

Answer :B