Question

ctg (arcsin1-arcctg2)

Answer 1

ctg (arcsin 1 - arcctg 2)
 arcsin 1 = pi/2
ctg (arcsin 1 - arcctg 2) = ctg (pi/2 - arcctg 2) = tg (arcctg 2)
 a = arcctg 2, то ctg a = 2 => tg a = 1/ctg a = 1/2.