Question

Ajudem por favor .......

Answer 1

Tg (a) = [sen (a)]/[cos (a)]
Tg (a) = [sen (90 - b)]/[(cos (90 - b)]
Tg (a) = [sen (90) . cos (b) - cos (90) . sen (b)]/[cos (90) . cos (b) + sen (90) . cos (b)]
Tg (a) = [1 . cos (b) - 0]/[1. sen (b) + 0]
Tg (a) = cos (b)/sen (b)
Tg (a) = 1/Tg (b)