ISRO Electronics & Communication (ECE) 2011 - Question 11

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Topic: Mathematics

$(3+i)/(5+5i)$ is same as

  • A. $(2-i)/5$
  • B. 3-i
  • C. 5-5i
  • D. $(2+i)/5$

Answer: A. $(2-i)/5$

Explanation: $\frac{3+i}{5+5i}=\frac{3+i}{5(1+i)}\times\frac{1-i}{1-i}=\frac{3-3i+i+1}{5(1+1)} = \frac{2(2-i)}{5\times2}=\frac{(2-i)}{5}$.

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