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8151.

Find derivatives of the following functionssqrt log x

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SOLUTION :`y = SQRT log x
dy/dx =1/(2sqrt log x).d/dx (log x) = 1/(2 sqrt log x).1/x`
8152.

If A'=[{:(-2,3),(1,2):}]andB=[{:(-1,0),(1,2):}]then find (A+2B)'.

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ANSWER :`=[{:(-4,5),(1,6):}]`
8153.

Find point on y=2x-3 nearest to origin.

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ANSWER :`((6)/(5),-(3)/(5))`
8154.

By using elementary row operations, find the inverese of the martrix A=[{:(1,3,-2),(-3,0,-5),(2,5,0):}].

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Solution :We have
`[{:(1,3,-2),(-3,0,-5),(2,5,0):}]=[{:(1,0,0),(0,1,0),(0,0,1):}].A`
`implies""[{:(1,3,-2),(0,9,-11),(0,-1," "4):}]=[{:(1,0,0),(3,1,0),(-2,0,1):}].A""[{:(R_(2)toR_(2)+3R_(1)),(R_(3)toR_(3)-2R_(1)):}]`
`implies""[{:(1,3,-2),(0,-1," "4),(0,9,-11):}]=[{:(1,0,0),(-2,0,1),(3,1,0):}].A""[R_(2)harrR_(3)]`
`implies""[{:(1,0,10),(0,-1,4),(0,0,25):}]=[{:(-5,0,3),(-2,0,1),(-15,1,9):}].A""[{:(R_(1)toR_(1)+3R_(2)),(R_(3)toR_(3)+9R_(2)):}]`
`implies""[{:(1,0,10),(0,1,-4),(0,0,25):}]=[{:(-5,0,3),(" "2,0,-1),(-15,1,9):}].A""[{:(R_(2)tp(-1).R_(2)]`
`implies""[{:(1,0,10),(0,1,-4),(0,0,1):}]=[{:(-5,0,3),(2,0,-1),((-3)/(5),(1)/(25),(9)/(25)):}].A" "[R_(3)to(1)/(25)R_(3)]`
`implies""[{:(1,0,0),(0,1,0),(0,0,1):}]=[{:(1,(-2)/(5),(-3)/(5)),((-2)/(5),(4)/(25),(11)/(25)),((-3)/(5),(1)/(25),(9)/(25)):}].A""[{:(R_(1)toR_(1)-10R_(3)),(R_(2)toR_(2)+4R_(3)):}].`
Hence, `A^(-1)=[{:(1,(-2)/(5),(-3)/(5)),((-2)/(5),(4)/(25),(11)/(25)),((-3)/(5),(1)/(25),(9)/(25)):}].`
8155.

int(1+sinx)/(1-sinx)dx

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SOLUTION :`I=INT(1+sinx)/(1-sinx)DX`
=`int(1+sinx)^2/cos^2xdx`
=`int(sec^2x+tan^2x+2secxtanx)dx`
=`int(2sec^2x-1+2secxtanx)dx`
=2tanx-x+2secx+c
8156.

Find the area of the region bounded by y= cos x and y= sin 2x between x=0 and x=(pi)/(2)

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ANSWER :`((1)/(2))`
8157.

Evaluate :tan^(-1){2cos(2sin^(-1)""(1)/2)}

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ANSWER :`pi/4`
8158.

Let n and k be positive integers such that n ge(k(k+1))/2. Find the number of solutions (x_(1),x_(2),x_(3),……………x_(k)), x_(1)ge1,x_(2)ge2,……………..,x_(k)gek, all integers satisfying the condition x_(1)+x_(2)+x_(3)+…………….1x_(k)=n.

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ANSWER :`.^(m+K-1)C_(k-1)`, where `m=n(k(k+1))/2`
8159.

If ""^(n)C_(r)+3""^(n)C_(r+1)+3""^(n)C_(r+2)+""^(n)C_(r+3)=""^(15)C_(9) ,then which of the following is true?

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n=12
r=6
r=3
n=11

Answer :A::B::C
8160.

Find the slope of the lines whose inclinations are given.45^@.

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SOLUTION :SLOPE = `TAN45^@`=+1.
8161.

The tangent to the curve y=e^(2x) at the point (0, 1) meets X-axis at :

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

ANSWER :B
8162.

Evaluate the following integrals (vii) int_(0)^(pi//2) (1)/( 2+3 sin x) dx

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ANSWER :`(1)/(SQRT(5)) LOG ((5+sqrt(5))/(5-sqrt(5)))`
8163.

Integrate the following functions : intcosxsqrt(9-sin^(2)x)dx

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ANSWER :`(sinx)/(2)sqrt(9-sin^(2)x)+(9)/(2)sin^(-1)((sinx)/(3))+C`
8164.

(4)/(1.3)-(6)/(2.4)+(12)/(5.7)-(14)/(6.8)+….=

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`log_(E )((2)/(e ))`
`log_(e )((e )/(2))`
`log_(e)2`
0

Answer :C
8165.

Find the principal value of cos^-1(frac(sqrt3)(2))

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SOLUTION :`COS (pi/6)=sqrt3/2`and `pi/6 in [0,pi]`
`therefore`The principal VALUE of `cos^(-1)(sqrt3/2)=pi/6`
8166.

The mean deviation of the data 3, 5, 11, 13, 17, 19, 23, 29 about its arithmetic mean is

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A.8.5
B.8
C.7.2
D.7

Answer :D
8167.

If A(bara), B(barb), C(barc) and D(bard) are the four points such that 3bara + 8barb = 6barc + 5bard, then the lines AB and CD are

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SKEW
INTERSECTING
PARALLEL
non-coplanar

ANSWER :B
8168.

int(3x+4)/sqrt(2x-3)dx

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Solution :`INT(3x+4)/sqrt(2x-3)DX` [Put 2x-3=t^2
Then 2dx=2tdt
or dx=tdt]
=`int(3((t^2+3)/2)+4)/t .tdt`
=`3/2intt^2dt+17/2intdt=3/2.t^3/3+17/2t+C`
=`1/2t^3+17/2t+C`
=`1/2(2x-3)^(2/3) +17/2(2x-3)^(1/2) +C`
=`(x+7)sqrt(2x-3)dx`
8169.

If int_(0)^(4pi)ln|13sinx+3sqrt3cosx|dx=kpiln7, thenthe value of k is

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2
4
8
16

Solution :`int_(0)^(4pi)ln|13sinx+3sqrt3cosx|dx`
`=4int_(0)^(4pi)ln|14sin(x+tan^(-1).(3sqrt3)/(13))|dx`
`=8int_(0)^(pi//2)(ln14+log|sinx|)dx`
`=4pi(ln14-ln2)=4piln7.`
8170.

A rod PQ of length 2a sides with its ends on the axes the locus of the circumcentre of triangleOPQ is

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`X^(2)+y^(2)=2a^(2)`
`x^(2)+y^(2)=4A^(2)`
`x^(2)+y^(2)=3A^(2)`
`x^(2)+y^(2)=a^(2)`

ANSWER :D
8171.

Let f(x)=int((4x^(4)-2x^(3)-3x^(2)-4)dx)/((x^(4)+x^(3)+1)^(3//2)). If f(0)=2, then the value of f(-1) is

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6
10
1
none of these

Answer :A
8172.

A bag contains a total of 20 books on physics and mathematics, Anypossible combination of books is equally likely. Ten books are chosen from the bag and it is found that it contains 6 books of mathematics. Find out the probability that the remaining books in the bag contains 3 books on mathematics.

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Solution :Let `E_(i)(i=0,1,2,...,20)` be the event that the bag contains I books on MATHEMATICS. Since all these events are equally likely and mutually EXCLUSIVE and exhaustive, so `P(E_(1))=1//21(i=0,1,2,....,20)`and let A be the event that a drw of 10 books contains 6 books on matematics Then
So, USING Bay's THEOREM,
`P(A)=underset(i=0)overset(20)sumP(E_(i)).P(A//E_(i))`
`=1/21[underset(i=0)overset(20)sumP(A//E_(i))]`
`=1/21[underset(i=6)overset(16)sum(""^(i)C_(6)xx""^(20-i)C_(4))/(""^(20)C_(10))]`
Now, we want that the bag should contain 2 more books on mathematics, i.e., `E_(8)` must occur.
Using Baye's theorem,
`P(E_(8)//A)=(P(E_(8))P(A//E_(8)))/(P(A))`
`=((""^(8)C_(6)xx""^(12)C_(4))/(""^(20)C_(10)))/(underset(i=6)overset(16)sum((""^(i)C_(6)xx""^(20-i)C_(4))/(""^(20)C_(10))))`
`=(""^(8)C_(6)xx""^(12)C_(4))/(underset(i=6)overset(16)sum(""^(i)C_(6)xx""^(20-i)C_(4)))`
8173.

Integrate the following functions (3x)/(1+2x^4)

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Solution :Let t = `sqrt2 x^2`. Then DT = `2 sqrt2 x dx`
`gt x dx = 1/(2 sqrt2) dt`
therefore` INT (3x)/(1+2x^4) dx = int 3/(1+t^2) 1/(2sqrt2) dt`
=`3/(2 sqrt2) tan^-1 t+C`
`3/(2 sqrt2) tan^-1 (sqrt2 x^2)+c`
8174.

Resolve (2x^(2)+1)/(x^(3)-1) into partial fractions.

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Answer :`:.(2X^(2)+1)/((x^(3)-1))=(1)/(x-1)+(x)/(x^(2)+x+1)`
8175.

Find the principal value of cosec^-1(-sqrt2)

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8176.

Determine the number of subsets of {1,2,3…70} whose sum is larger than 1243.

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ANSWER :`2^(69)`
8177.

Find the number of solutions in ordered paris of positive integers (x,y) of the equation 1/x+1/y=1/n where n is positive integer.

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Answer :`(2e_(1)+1)(2e_(2)+1).....(2e_(k)+1),` where `""n=p_1^(e_(1))p_2^(e_(2))...p_(k)^(e_k)`
8178.

If an infinite G.P. has 2nd term x and its sum is 4, then prove that xin(-8,1]-{0}

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Solution :Let the common ratio of G.P be r.
Since SECOND TERM is X,first terms is x/r
Now, sum of infinite terms of G.P.=4
`RARR(x/r)/(1-r)=4`
`thereforex=4(r-r^(2))`
For `rin(-1,-1)-{0}`, we have
`r-r^(2)=1/4-(r-1/2)^(2)in(-2,1/4]-{0}`
`rArrxin(-8,1]-{0}`
8179.

Two coins are tossed find the conditional probability that two tails result, given that there is atleast one tail.

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ANSWER :`(1)/(3)`
8180.

A coin is biased so that the head is 3 times as likely to occur as tail. If the coin is tossed twice, find the probability distribution of number of tails.

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ANSWER :`(##NCERT_TAM_MAT_XII_P2_C13_E04_007_A01##)`
8181.

Determine the integral values of k for which the system (tan^(-1)x)^(2)+(cos^(-1)y)^(2)=pi^(2)k and tan^(-1)x+cos^(-1)y=(pi)/2 possess solution and find all the solutions.

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SOLUTION :NA
8182.

Consider the regions A={(x,y)|x^(2)+y^(2)le100} and B=|(x,y)|sin(x+y)gt0} in the plane. Then the area of the region AnnB is

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`10pi`
100
`100pi`
`50pi`

Solution :`x^(2)+y^(2)le100`
`rArr "Points lies inside CIRCLE or on the circle."`
`SIN(x+y)gt0`
`x+y in (0,pi)uu(2pi,3pi)..`
`x+y=c` is equation of a line
Required area is shown in the following FIGURE :

`"Required area = shaded region"`
`"= HALF of the area of the circle "`
`=(1)/(2)pi(10)^(2)=50pi`
8183.

The probability that a bulb produced by a factory will fuse after 150 days of use is 0.05. Find the probability that out of 5 such bulbs (i) None(ii) Not more than one (iii) more than one(iv) at least one will fuse after 150 days of use?

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ANSWER :0.95
8184.

The range of the function is f(x) =""^(7-x)P_((x)-(x-3)) is

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{1,2,3,4}
{1,2,3,4,5,6}
{1,2,3}
{1,2,3,4,5}

ANSWER :C
8185.

If [vec(a),vec(b),vec(c)]=3andabsvec(c)=1" then "|(vec(b)xxvec(c))xx(vec(c)xxvec(a))| is

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1
3
6
9

Answer :C
8186.

If int(2x^2)/((2x^2+alpha)(x^2+5))dx =sqrt(5)/3 tan^(-1)"" x/sqrt2 +c ,"then alpha=

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1
2
3
4

Answer :D
8187.

For every natural number n, n(n^2-1) is divisible by

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4
6
10
None of these

ANSWER :B
8188.

If P, Q, R are angles of an isosceles triangle and sqrtP=pi//2, then the value of (cosP/3-isinP/3)^(3)+(cosQ+isinQ)(cosR-isinR)+(cosP-isinQ)(coisR-isinR) is equal to

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i
`-i`
1
`-1`

ANSWER :B
8189.

(dx)/((x+1)^(3)sqrt(x^(2)+3x+2)).

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Answer :`-(2)/(15)SQRT((x+2)/(x+1))(8x^(2)+12x+7)/((x+1)^(2))+C.`
8190.

lf L and L^(1) are ends or latusrectum of the parabola 9y^(2)= 4x then the combined equation of OL and OL^(1) is

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`4X^(2)=9Y^(2)`
`X^(2)=9y^(2)`
`x^(2)=4x^(2)`
`y^(2)=4x^(2)`

ANSWER :D
8191.

Two paralel straight lines indined at an angle theta to x-axis where (90^(@)lt theta lt 180^(@))meet the x-axis at points A, B and y -axis at points C and D respectively. If the equation of the locus of the point of intercectin of AD and BC is x -y =0, te slope of the lines is

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`-1`
` 1`
`-1 //SQRT3`
`1` //sqrt3`

ANSWER :A
8192.

int sqrt(cos 2x)/(sin x) dx =

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`1/(2sqrt(2))log |(SQRT(2)+sqrt(1-tan^(2)X))/(sqrt(2)-sqrt(1-tan^(2) x))|-1/2 log |(1-sqrt(1-tan^(2)x))/(1+sqrt(1-tan^(2)x))|+c`
`1/sqrt(2) log |(sqrt(2)+sqrt(1-tan^(2)x))/(sqrt(2)-sqrt(1-tan^(2) x))|-1/2 log |(1+sqrt(1-tan^(2) x))/(1-sqrt(1-tan^(2) x))|+c`
`1/(4 sqrt(2)) log |(sqrt(2)-sqrt(1-tan^(2) x))/(sqrt(2)+sqrt(1-tan^(2)x))|+1/2 log |(1-sqrt(1-tan^(2) x))/(1+sqrt(1-tan^(2) x))+c`
`1/(4sqrt(2)) log |(2-sqrt(1-tan^(2) x))/(2+sqrt(1-tan^(2) x))|+1/(2sqrt(2)) log |(1-sqrt(1-tan^(2)x))/(1+sqrt(1-tan^(2) x))|+c`

ANSWER :B
8193.

Compute the integral int_(1//2)^(sqrt(3//2)) (dx)/(x sqrt(1 - x^(2)))

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ANSWER :`I N (2 + SQRT(3))/( sqrt(3))`
8194.

If sales of potatoes were to increase by $173 next month and sales of all other items were held constant, approximately what percentage of the total sales would be be potatoes ?

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`20%`
`25%`
`30%`
`40%`

ANSWER :B
8195.

Let A=(2,3,7,9} , f:A rarr B is a function defined as f(x)=x^(2). Then find the range of f(x).

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8196.

Assertion (A) : The probability of getting exactly 2 heads in tossing a coind thrice is ((1)/(2))^(3) Reason (R ) : The probability of getting exactly r heads in tossing n coins is (.^(n)C_(r ))/(2^(n)). The correct answer is

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Both A and R are TRUE, R is the CORRECT EXPLANATION of A
Both A and R are true, R is not the correct explanation of A
A is true but R is false
A is false R is true

Answer :D
8197.

Examine the continuity of the following functions at indicated points.f(x)={(1/(e^(1/2)-1)ifxgt0 at x=0),(0 if xle0):}

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Solution :F(0)=0
R.H.L.=`lim_(xto0+)f(x)=lim_(hto0)(0+h)`
`=lim_(hto0)1/(E^(1/x)-1)=0`
`L.H.L.=lim_(xto0)f(x)=lim_(hto0)f(0-h)`
`=lim_(hto0)0=0`
8198.

Identify the constant function if any. {(a,1),(b,1),(c,1)}

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SOLUTION :The FUNCTION {(a,1),(b,1),(c,1)} is a CONSTANT function.
8199.

((x+1))/((2x-1)(3x+1))=A/((2x-1))+B/((3x+1)) rArr 16A+9B=

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4
5
6
8

Answer :C
8200.

If a parallelogram ABCD, |AB|=a, |AD|=b and |AC|=C, then DA. AB is equal to

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`(1)/(2)(a^(2)+b^(2)+c^(2))`
`(1)/(2)(a^(2)-b^(2)+c^(2))`
`(1)/(4)(a^(2)+b^(2)-c^(2))`
`(1)/(3)(b^(2)+c^(2)-a^(2))`

SOLUTION :We have, `|AB|=a, |AD|=b, |AC|=c`

In `Delta ABC,""AB + BC = AC `
`rArr AB+AD=AC "" [ because BC=AD]`
`rArr AB-DA=AC "" [ because AD=-DA]`
`rArr |AB-DA|=|AC|`
`rArr |AB-DA|^(2)=|AC|^(2)`
`rArr |AB|^(2)+|DA|^(2)-2AB*DA=(AC)^(2)`
`rArr a^(2)+b^(2)-2AB*DA=c^(2) "" [ because |AD|=|DA|=b]`
`rArr 2DA *AB=a^(2)+b^(2)-c^(2)`
`rArr DA*AB=(1)/(2)[a^(2)+b^(2)-c^(2)]`