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Question: Answered & Verified by Expert
If $z=\frac{7-i}{3-4 i}$ then $z^{14}=$
MathematicsComplex NumberJEE Main
Options:
  • A $2^7$
  • B $2^7 i$
  • C $2^{14} i$
  • D $-2^7 i$
Solution:
1093 Upvotes Verified Answer
The correct answer is: $-2^7 i$
$\begin{aligned} & z=\frac{7-i}{3-4 i} \times \frac{3+4 i}{3+4 i}=\frac{21+25 i+4}{16+9}=\frac{25(1+i)}{25}=(1+i) \\ & z^{14}=(1+i)^{14}=\left[(1+i)^2\right]^7=(2 i)^7=2^7 i^7=-2^7 i .\end{aligned}$

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