4-1.Complex numbers
medium

यदि $n$ एक धनात्मक पूर्णांक हो, तो ${\left( {\frac{{1 + i}}{{1 - i}}} \right)^{4n + 1}}$=

A

$1$

B

$-1$

C

$i$

D

$ - i$

Solution

(c) $\frac{{1 + i}}{{1 – i}} = \frac{{(1 + i)(1 + i)}}{{(1 – i)(1 + i)}} = i$

इसलिए ${\left( {\frac{{1 + i}}{{1 – i}}} \right)^{4n + 1}} = {i^{4n + 1}} = i{i^{4n}} = i\,\,\,\,\,(\because {i^{4n}} = 1)$

Std 11
Mathematics

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