Question

Cotπ/20cot3π/20cot5π/20cot7π/20cot9π/20cot15π/20

Answer 1

Answer:

-1

Step-by-step explanation:

Cotπ/20cot3π/20cot5π/20cot7π/20cot9π/20cot15π/20

=> Cot 9 * Cot 27 * cot 45 * cot 63 * cot 81 * cot 135

=> Cot 9 * Cot 27 * cot 45 * cot (90 - 27) * cot (90 - 9) * Cot (90+45)

=> Cot 9 * Cot 27 * cot 45 * tan 27 * tan 9 * (- tan 45)

=> 1/tan 9 * 1/tan 27 * tan27 * tan 9 * cot 45 * (-tan45)

=> cot 45 * (-tan 45)

=> 1 * ( - 1 )

=> - 1.