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Question -

Find the multiplicative inverse of the following complex numbers:

(i) 1 – i

(ii) (1 + i √3)2

(iii) 4 – 3i

(iv) √5 + 3i



Answer -

(i) 1 – i

Given:

1 – i

We know themultiplicative inverse of a complex number (Z) is Z-1 or 1/Z

So,

The multiplicativeinverse of (1 – i) is (1 + i)/2

(ii) (1 + i √3)2

Given:

(1 + i √3)2

Z = (1 + i √3)2

= 12 +(i √3)2 + 2 (1) (i√3)

= 1 + 3i2 +2 i√3

= 1 + 3(-1) + 2 i√3[since, i2 = -1]

= 1 – 3 + 2 i√3

= -2 + 2 i√3

We know themultiplicative inverse of a complex number (Z) is Z-1 or 1/Z

So,

Z = -2 + 2 i√3

The multiplicativeinverse of (1 + i√3)2 is (-1-i√3)/8

(iii) 4 – 3i

Given:

4 – 3i

We know themultiplicative inverse of a complex number (Z) is Z-1 or 1/Z

So,

Z = 4 – 3i

The multiplicativeinverse of (4 – 3i) is (4 + 3i)/25

(iv) √5 + 3i

Given:

√5 + 3i

We know themultiplicative inverse of a complex number (Z) is Z-1 or 1/Z

So,

Z = √5 + 3i

The multiplicativeinverse of (√5 + 3i) is (√5 – 3i)/14

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