Complex NumbersHard
Question
If 2 cosθ = x + 
and 2 cos φ = y + 
, then
and 2 cos φ = y + , thenOptions
A.xn + 
= 2 cos (nθ)
= 2 cos (nθ)B.
= 2 cos (θ - φ)
= 2 cos (θ - φ)C.xy + 
= 2 cos (θ + φ)
= 2 cos (θ + φ)D.none of these
Solution
(A) x = eiθ y = eiφ
xn +
= 2 cosnθ
(B)
= ei(θ - φ) + e - i(θ - φ) = 2 cos(θ - φ)
(C) xy +
= 2cos(θ + φ)
xn +
= 2 cosnθ(B)
= ei(θ - φ) + e - i(θ - φ) = 2 cos(θ - φ)(C) xy +
= 2cos(θ + φ)Create a free account to view solution
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