Question

Prove:- cos(pi)/(15)cos(2 pi)/(15)cos(3 pi)/(15)cos(4 pi)/(15)cos(pi)/(15)cos(pi)/(15)cos6 pi)/(15) cos(7 pi)/(15)=(1)/(128)​

Answer 1

Answer:

refer to the attachments

Step-by-step explanation:

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Answer 2

""" ❤️ Answer ❤️ ""'

LHS=cosπ15cos2π15cos4π15cos3π

=cosπ15cos2π15cos4π15(cos3π15

=−12[cosπ15cos2π15cos4π15cos8π

=−12×2324sinπ15[2sinπ15cosπ15cos

=−23132sinπ15[sin2π15cos2π15cos4

=−2232sinπ15[2sin2π15cos2π15cos4

=−232sinπ15[sin8π15cos8π15]×sin12

=−132sinπ15[sin16π15]×sin12π154sin

=−sin(π+π15)128sinπ15×sin(π−3π15)

=−−sinπ15128sinπ15×sin3π15sin3π15

=1128

=RHS

Hence proved

Hence proved.