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महाराष्ट्र राज्य शिक्षण मंडळएचएससी विज्ञान (सामान्य) इयत्ता ११ वी

Answer the following: show that ii(1+i2)8+(1-i2)8 = 2

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प्रश्न

Answer the following:

show that `((1 + "i")/sqrt(2))^8 + ((1 - "i")/sqrt(2))^8` = 2

बेरीज
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उत्तर

`((1 + "i")/sqrt(2))^2 = (1 + 2"i" + "i"^2)/2 = (1 + 2"i" - 1)/2` = i

∴ `((1 + "i")/sqrt(2))^8 = [((1 + "i")/sqrt(2))^2]^4` = i4 = 1 .......(i)

Also, `((1 - "i")/sqrt(2))^2 = (1 - 2"i" + "i"^2)/2 = (1 - 2"i" - 1)/2` = – i

∴ `((1 - "i")/sqrt(2))^8 = [((1 - "i")/sqrt(2))^2]^4`

= (– i)4 = (– 1)4 × (i)4

= 1 × i4

= 1 ........(ii)

Adding (i) and (ii), we get

`((1 + "i")/sqrt(2))^8 + ((1 - "i")/sqrt(2))^8` = 1 + 1 = 2

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

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

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