Question

cos(π/ 20)cos(3π/20)cos(5π/20)cos(7π/20)cos(9π/20)=1 then process is
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Answer 1

Step-by-step explanation:

please refer to the above attachment

Answer 2

Answer:

Step-by-step explanation:

=Cotπ/20 cot3π/20 cot5π/20 cot7π/20 cot9π/20

=Cotπ/20 cot3π/20 cotπ/4 cot (π/2-3π/20) cot(π/2-π/20)

=Cotπ/20 cot3π/20 1 tan3π/20 tanπ/20

=1