TRIGONOMETRI II
a + b + 90° = 180°
a + b = 90°
b = 90° -a
sin a + cos b = ½
sin a + cos (90° -a) = ½
sin a + sin a = ½
2 sin a = ½
sin a = ¼ = a/c
cos²a = 1 -sin²a
cos²a = 1 -1/16 = 15/16
cos a = ¼√15
tan a = sin a/cos a
tan a = 1/15 √15
csc b = 1/sin
= 1/cos a
= 4/15 √15
tan a -csc
= 1/15 √15 -4/15 √15
= 3/15 √15
= ⅕√15
