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महाराष्ट्र राज्य शिक्षण मंडळएचएससी विज्ञान (सामान्य) इयत्ता ११ वी

Answer the following: Show that z = 5(1-i)(2-i)(3-i) is purely imaginary number.

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प्रश्न

Answer the following:

Show that z = `5/((1 - "i")(2 - "i")(3 - "i"))` is purely imaginary number.

बेरीज
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उत्तर

z = `5/((1 - "i")(2 - "i")(3 - "i"))` 

= `5/((2 - "i" - 2"i" + "i"^2)(3 - "i"))`

= `5/((2 - 3"i" - 1)(3 - "i"))`    ...[∵ i2 = – 1]

= `5/((1 - 3"i")(3 - "i"))`

= `5/(3 - "i" - 9"i" + 3"i"^2`

= `5/(3 - 10"i" - 3)`

= `5/(-10"i")`

= `(5"i")/(-10"i"^2)`

= `(5"i")/10`

= `1/2"i"`, which is a purely imaginary number.

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पाठ 1: Complex Numbers - Miscellaneous Exercise 1.2 [पृष्ठ २२]

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बालभारती Mathematics and Statistics (Arts and Science) Part 2 [English] Standard 11 Maharashtra State Board
पाठ 1 Complex Numbers
Miscellaneous Exercise 1.2 | Q II.08 | पृष्ठ २२

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