(Q16-Q20) : (1 - 2) Introduction in Complex Numbers.

 

1sec ≫ First term  ≫ Algebra ≫ Unit 1 ≫ (1-2 )  introduction to complex numbers :

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(Q16 To Q20)

[16] If \( n \in \mathbb{Z} \), then \( i^{12n-7} =..........\)

(a) \( i \)
(b) \( -i \)
(c) -1
(d) 1

The correct answer is: (a) \( i \)

[17] If \( n \in \mathbb{Z} \), then \( i^{4n+50} = \) ............

(a) 1
(b) -1
(c) \( -\mathrm{i} \)
(d) \( \mathrm{i} \)

The correct answer is: (b) -1

(18) The conjugate of the number \( (3i - 4) \) is .................

(a) \( 3\mathrm{i} + 4 \)
(b) \( -3\mathrm{i} - 4 \)
(c) \( -3\mathrm{i} + 4 \)
(d) \( 3\mathrm{i} - 4 \)

The correct answer is: (b) \( -3\mathrm{i} - 4 \)

[19] The conjugate of the complex number \( (4 - 7i) \) is ...........

(a) \( 4 + 7i \)
(b) \( -4 + 7i \)
(c) \( -4 - 7\mathrm{i} \)
(d) \( 4 - 7\mathrm{i} \)

The correct answer is: (a) \( 4 + 7i \)

[20] The conjugate of the number \( (2 + \mathrm{i})^{2} \) is .............

(a) \( 2 + \mathrm{i} \)
(b) \( (2 + \mathrm{i})^{-1} \)
(c) \( 3 + 4\mathrm{i} \)
(d) \( 3 - 4\mathrm{i} \)

The correct answer is: (d) \( 3 - 4\mathrm{i} \)