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Mathematics Test - 28
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Mathematics Test - 28
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  • Question 1/10
    1 / -0

    The range of the real-valued function f(x)=9x2 is:

    Solutions

    Given: f(x)=9x2

    Let, y2=9x2

    x2=9y2

    x=9y2(1)

    We know that for any function f(x)=9x2,y0. (A)

    From equation (1).

    9y20

    y290

    (y+3)(y3)0

    3y3

    But from equation (A) y must be positive, then, y=[0,3].

    Range = the value of y=[0,3]

  • Question 2/10
    1 / -0

    Let SK1+2++KK and j=1nSj2=nA(Bn2+Cn+D), where A,B,C,DN and A has least value. Then:

    Solutions

    Sk=k+12 Sk2=k2+1+2k4j1nSj2=14[n(n+1)(2n+1)6+n+n(n+1)]=n4[(n+1)(2n+1)6+1+n+1]=n4[2n2+3n+16+n+2]=n4[2n2+9n+136]=n24[2n2+9n+13]A=24,B=2,C=9,D=13

  • Question 3/10
    1 / -0

    All the pairs (x,y) that satisfy the inequality 2sin2x2sinx+514sin2y1 also satisfy the equation:

    Solutions

    Given inequality is,

    2sin2x2sinx+52sin2y

    sin2x2sinx+52sin2y

    (sinx1)2+42sin2y

    It is true if sinx=1 and |siny|=1

    Therefore, sinx=|siny|

  • Question 4/10
    1 / -0

    Evaluate the integral 14x+3xdx.

    Solutions

    I=14x+3xdx

    Let x+3=t(i)

    Differentiating w.r.t x, we get,

    12xdx=dt

    1xdx=2dt

    The new limits to eqn(i)

    When x=1,1+3=t

    t=4

    Similarly,

    When x=4,t=5

    14x+3xdx=452tdt

    =2×[t22]45

    =[t2]45

    Put the value of limit,

    =[5242]

    =9

  • Question 5/10
    1 / -0

    If A={2,3,4} and B={5,6}, then how many subsets does A×B have?

    Solutions

    Given:

    A={2,3,4};B={5,6}

    We know that:

    For any two non-empty sets A and B, we have:

    I. A×B={(a,b)aA and bB}

    II. B×A={(b,a)aA and bB}

    III. Any two ordered pairs (a,b)=(c,d) if and only if a=c and b=d.

    Then,

    A×B={(2,5),(2,6),(3,5),(3,6),(4,5),(4,6)}

    The number of elements in A×B i.e.,

    n(A×B)=6

    Therefore, the number of subsets ofA×B=2n

    =26

    =64

    Therefore, there are 64 subsets for A×B.

  • Question 6/10
    1 / -0

    If P and Q be two sets such that PQ=P, then PQ will be:

    Solutions

    Intersection:

    Let A and B be two sets. The intersection of A and B is the set of all those elements which are present in both sets A and B.

    The intersection of A and B is denoted by A ∩ B

    i.e., A ∩ B = {x : x ∈ A and x ∈ B}

    The Venn diagram for intersection is as shown below:

    Union:

    Let A and B be two sets. The union of A and B is the set of all those elements which belong to either A or B or both A and B.

    The union of A and B is denoted by A ∪ B.

    i.e., A ∪ B = {x : x ∈ A or x ∈ B}

    The Venn diagram for the union of any two sets is shown below:

    A ∪ B = A + B - A ∩ B

    As we know, 

    P ∪ Q = P + Q - P ∩ Q

    Putting the values given in the question,

    P = P + Q -  P ∩ Q

    P ∩ Q = Q

  • Question 7/10
    1 / -0

    Let S be the set of all real roots of the equation, 3x(3x1)+2=3x1|+3x2|. Then S:

    Solutions

    Let 3x=y

    y(y1)+2=|y1|+|y2|

    Case 1: when y>2

    y2y+2=y1+y2

    y23y+5=0

    D<0[ Equation not satisfy. ] 

    Case 2 : when 1y2

    y2y2+2=y1y+2

    y2y+1=0

    D<0[ Equation not satisfy. ]

    Case 3: when y1

    y2y+2=y+1y+2

    y2+y1=0

    y=1+52

    =152[ Equation not Satisfy ]

    Only one 1+52 satisfy equation

  • Question 8/10
    1 / -0

    If the mean of 4, 7, 2, 8, 6 and a is 7, then the mean deviation from the median of these observations is:

    Solutions

  • Question 9/10
    1 / -0

    Find the number of arrangements of letters in the word ASHUTOSH?

    Solutions

    Given word is : ASHUTOSH

    Total 8 letters are there, in which letter S and H are repeated twice.

    We know that:Number of Permutations of 'n' things taken 'r' at a time:p(n,r)=n!(nr)!

    Number of Permutations of ‘n’ objects where there are n1 repeated items, n2 repeated items, nk repeated items taken ‘r’ at a time:p(n,r)=n!n1!n2!n3!nk!

    Therefore,The number of arrangements will be:

    p(8,2)=8×7×6×5×4×3×2!(2×1)2!=10080

    Therefore, the number of arrangements of letters in the word ASHUTOSH will be 10080

  • Question 10/10
    1 / -0

    If the constraints in a linear programming problem are changed _______________.

    Solutions

    If the constraints in a linear programming problem are changed the problem is to be re-evaluated.The linear inequalities or equations or restrictions on the variables of a linear programming problem are called constraints. The conditions x ≥ 0, y ≥ 0 are called non-negative restrictions.

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