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महाराष्ट्र राज्य शिक्षण मंडळएचएससी विज्ञान (सामान्य) इयत्ता ११ वी

Express the following in the form of a + ib, a, b∈R i = −1. State the values of a and b: (1 + 2i)(– 2 + i)

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प्रश्न

Express the following in the form of a + ib, a, b ∈ R, i = `sqrt(−1)`. State the values of a and b:

(1 + 2i)(– 2 + i)

बेरीज
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उत्तर

(1 + 2i)(– 2 + i)

= – 2 + i – 4i + 2i2

= – 2 – 3i – 2   ...[∵ i2 = – 1]

= – 4 – 3i

This is of the form a + bi, where a = – 4 and b = – 3.

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पाठ 1: Complex Numbers - Exercise 1.1 [पृष्ठ ६]

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