Question

Find a cofunction with the same value as sin 19 degrees

Answer 1

func(a) = cofunc(90 - a)
so,
sin(19) = cos(71)

similarly,

tan(19) = cot(71)
sec(19) = csc(71)

co-func is just short for "complementary"

Answer 2

=Sin(90-71)/cos71
=cos71/cos71
=1