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AP EAMCET · Maths · Complex Number

Real part of (cos4+isin4+1)2020 is_______

  1. A 22020cos20202cos2020
  2. B 22020cos20202cos4040
  3. C 21020cos20202cos4040
  4. D 22020cos20201cos2020
Verified Solution

Answer & Solution

Correct Answer

(B) 22020cos20202cos4040

Step-by-step Solution

Detailed explanation

Given, (cos4+isin4+1)2020 Now using, 1+cos2A=2cos2A and sin2A=2sinAcosA, we get 2cos22+2isin2cos22020 ⇒2cos2cos2+isin22020 Now, By using De Moivre's Theorem, we get ⇒22020cos20202cos2×2020+isin2×2020 ⇒22020cos20202cos4040+isin4040 Hence, the Real part…
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