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MHT CET · Maths · Complex Number

If \(Z_1=4 \mathrm{i}^{40}-5 \mathrm{i}^{35}+6 \mathrm{i}^{17}+2, \mathrm{Z}_2=-1+\mathrm{i}\), where \(\mathrm{i}=\sqrt{-1}\), then \(\left|\mathrm{Z}_1+\mathrm{Z}_2\right|=\)

  1. A 5
  2. B 13
  3. C 12
  4. D 15
Verified Solution

Answer & Solution

Correct Answer

(B) 13

Step-by-step Solution

Detailed explanation

\(\mathrm{Z}_1=4 \mathrm{i}^{40}-5 \mathrm{i}^{35}+6 \mathrm{i}^{17}+2\)
\(\mathrm{Z}_1=6+11 \mathrm{i}\)
\(\mathrm{Z}_2=-1+\mathrm{i}\)
\(\therefore \mathrm{Z}_1\) \(+~\mathrm{Z}_2=6+11 \mathrm{i}-1+\mathrm{i}\)
\(=5+12 \mathrm{i}\)
\(\therefore \left|\mathrm{Z}_1+\mathrm{Z}_2\right|=\sqrt{(5)^2+(12)^2}=\sqrt{169}=13\)