JEE MATHEMATICS MCQ: COMPLEX NUMBERS

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Application +4 | -1

The number of values of

\theta \in(0, \pi]

, such that (

\cos \theta+

i \sin \theta)(\cos 3 \theta+i \sin 3 \theta)(\cos 5 \theta+i \sin 5 \theta)(\cos 7 \theta

+i \sin 7 \theta)(\cos 9 \theta+i \sin 9 \theta)=-1

View answer and explanation

Correct option: B

Option B (13) is correct because solving the equation cos(25θ) = -1 within the given interval (0, π] yields 13 possible values for θ.

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