(iv) ((3+4i)(4+5i))/((4+3i)(6+7i))

3 min read Jun 16, 2024
(iv) ((3+4i)(4+5i))/((4+3i)(6+7i))

Simplifying Complex Fractions: A Step-by-Step Guide

This article will guide you through simplifying the complex fraction:

((3 + 4i)(4 + 5i)) / ((4 + 3i)(6 + 7i))

1. Expanding the Numerator and Denominator

First, we'll expand both the numerator and the denominator using the FOIL method (First, Outer, Inner, Last):

Numerator: (3 + 4i)(4 + 5i) = (3 * 4) + (3 * 5i) + (4i * 4) + (4i * 5i) = 12 + 15i + 16i + 20i²

Denominator: (4 + 3i)(6 + 7i) = (4 * 6) + (4 * 7i) + (3i * 6) + (3i * 7i) = 24 + 28i + 18i + 21i²

2. Simplifying using i² = -1

Recall that i² = -1. Substitute this value into both the numerator and denominator:

Numerator: 12 + 15i + 16i + 20i² = 12 + 15i + 16i - 20 = -8 + 31i

Denominator: 24 + 28i + 18i + 21i² = 24 + 28i + 18i - 21 = 3 + 46i

3. Multiplying by the Conjugate of the Denominator

To eliminate the imaginary part in the denominator, we'll multiply both the numerator and denominator by the conjugate of the denominator. The conjugate of 3 + 46i is 3 - 46i.

((3 + 4i)(4 + 5i)) / ((4 + 3i)(6 + 7i)) = ((-8 + 31i) * (3 - 46i)) / ((3 + 46i) * (3 - 46i))

4. Expanding and Simplifying

Again, using the FOIL method:

Numerator: (-8 + 31i)(3 - 46i) = (-8 * 3) + (-8 * -46i) + (31i * 3) + (31i * -46i) = -24 + 368i + 93i - 1426i² = -24 + 368i + 93i + 1426 = 1402 + 461i

Denominator: (3 + 46i)(3 - 46i) = (3 * 3) + (3 * -46i) + (46i * 3) + (46i * -46i) = 9 - 138i + 138i - 2116i² = 9 + 2116 = 2125

5. Final Simplification

Now we have:

((3 + 4i)(4 + 5i)) / ((4 + 3i)(6 + 7i)) = (1402 + 461i) / 2125

This can be expressed in the standard form of a complex number:

((3 + 4i)(4 + 5i)) / ((4 + 3i)(6 + 7i)) = (1402/2125) + (461/2125)i

Therefore, the simplified form of the given complex fraction is (1402/2125) + (461/2125)i.

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