Let  ω be a complex number such that 2ω +1 = z where z = √-

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 Multiple Choice QuestionsMultiple Choice Questions

1.

If P = open square brackets table row 1 straight alpha 3 row 1 3 3 row 2 4 4 end table close square brackets is the adjoint of a 3 x3 matrix A and |A| = 4, then α is equal to 

  • 4

  • 11

  • 5

  • 5

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2.

Let A = open square brackets table row 1 0 0 row 2 1 0 row 3 2 1 end table close square brackets. If u1 and u2 are column matrices such that Au1 = open square brackets table row 1 row 0 row 0 end table close square brackets and Au2 = open square brackets table row 0 row 1 row 0 end table close square brackets, then u1 +u2 is equal to

  • open square brackets table row cell negative 1 end cell row 1 row 0 end table close square brackets
  • open square brackets table row cell negative 1 end cell row cell space space space 1 end cell row cell negative 1 end cell end table close square brackets
  • open square brackets table row cell negative 1 end cell row cell negative 1 end cell row 0 end table close square brackets
  • open square brackets table row cell negative 1 end cell row cell negative 1 end cell row 0 end table close square brackets
480 Views

3.

Let A and B be two symmetric matrices of order 3.
Statement-1: A(BA) and (AB)A are symmetric matrices.
Statement-2: AB is symmetric matrix if matrix multiplication of A with B is commutative.

  • Statement-1 is true, Statement-2 is true; Statement-2 is a correct explanation for Statement-1.

  • Statement-1 is true, Statement-2 is true; Statement-2 is true; Statement-2 is not a correct explanation for Statement-1.

  • Statement-1 is true, Statement-2 is false. 

  • Statement-1 is true, Statement-2 is false. 

191 Views

4.

The number of 3 × 3 non-singular matrices, with four entries as 1 and all other entries as 0, is 

  • less than 4

  • 5

  • 6

  • 6

178 Views

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5.

Let f : R → R be defined by
straight f left parenthesis straight x right parenthesis space equals space open curly brackets table attributes columnalign left end attributes row cell straight k minus 2 straight x comma if space straight x space less or equal than space minus 1 end cell row cell 2 straight x space plus 3 comma space if space straight x greater than negative 1 end cell end table close
If f has a local minimum at x = - 1 then a possible value of k is

  • 1

  • 0

  • -1/2

  • -1/2

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6.

If S is the set of distinct values of 'b' for which the following system of linear equations
x + y + z = 1
x + ay + z = 1
ax + by + z = 0
has no solution, then S is

  • a singleton

  • an empty set

  • an infinite set

  • an infinite set

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7.

Let  ω be a complex number such that 2ω +1 = z where z = √-3. if

open vertical bar table row 1 1 1 row 1 cell negative straight omega squared end cell cell straight omega squared end cell row 1 cell straight omega squared end cell cell straight omega to the power of 7 end cell end table close vertical bar space equals space 3 straight k
then k is equal to 

  • 1

  • -z

  • z

  • z


B.

-z

Here ω is complex cube of unity

straight R subscript 1 rightwards arrow with space on top straight R subscript 1 space plus straight R subscript 2 space plus space straight R subscript 3
space equals space open vertical bar table row 1 0 0 row 1 cell negative straight omega squared minus 1 end cell cell straight omega squared end cell row 1 cell straight omega squared end cell straight omega end table close vertical bar
space equals space 3 left parenthesis negative 1 minus straight omega minus straight omega right parenthesis space equals space minus space 3 straight z
rightwards double arrow space straight k space equals space minus straight z

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8.

Let a, b, c be such that 0 (a +c) ≠ . If open vertical bar table row cell space space space straight a end cell cell straight a plus 1 end cell cell space space straight a minus 1 end cell row cell negative straight b end cell cell straight b plus 1 end cell cell space space straight b minus 1 end cell row cell space space space straight c end cell cell space straight c minus 1 end cell cell space space straight c plus 1 end cell end table close vertical bar plus open vertical bar table row cell straight a plus 1 end cell cell straight b plus 1 end cell blank row cell straight a minus 1 end cell cell straight b minus 1 end cell cell straight c plus 1 end cell row cell left parenthesis negative 1 right parenthesis to the power of straight n plus 2 end exponent straight a end cell cell left parenthesis negative 1 right parenthesis to the power of straight n plus 1 end exponent straight b end cell cell left parenthesis negative 1 right parenthesis to the power of straight n space straight c end cell end table close vertical bar space equals space 0,then the value of 'n' is 

  • 0

  • any even integer

  • any odd integer

  • any odd integer

167 Views

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9.

Let A be a 2 × 2 matrix
Statement 1 : adj (adj A) = A
Statement 2 : |adj A| = |A|

  • Statement–1 is true, Statement–2 is true, Statement–2 is a correct explanation for statement–1

  • Statement–1 is true, Statement–2 is true; Statement–2 is not a correct explanation for statement–1.

  • Statement–1 is true, statement–2 is false.

  • Statement–1 is true, statement–2 is false.

178 Views

10.

If A and B are square matrices of size n × n such that A2 − B2 = (A − B) (A + B), then which of the following will be always true?

  • A = B

  • AB = BA

  • either of A or B is a zero matrix

  • either of A or B is a zero matrix

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