Question

express trigonometric ratios of acute angle cot (-3888)​

Answer 1

cot(-3888) = -cot(3888) = -cot(21π + 108 )

Hence - cot(21π + 108 ) = -cot(108)

As cot(nπ + x ) = cot(x)

-cot(108) = -cot(π/2 + 18 ) = -(-tan(18)) = tan18 (ans)

As in the second quadrant tan and cot is negative .

Answer 2

cot(-3888)

-cot(3888)={2π×10+288}

=-cot (288)=-cot (180+108)

=-cot (108)=-cot (π\2+18)

=-(-tan18)

=tan18