Tentukan nilai perbandingan trigonometri utama yg lain jika : A. Cos a=3/5 dan sudut a terletak di kuadran I B. Sin a = -5/13 dan sudut a terletak di kuadran IV

A. cos a= sa÷mi = 3/5 > kuadran 1
mi^2 = sa^2 + de^2
5^2 = 3^2 + de^2
de^2 = 25-9 = 16
de = +4
sin = de/mi = 4/5
tan = de/sa = 4/3
sec = 1/cos= 5/3
cosec= 1/sin = 5/4
cotan = 1/tan = 3/4

B sin a = -de÷ mi = -5÷13 > kuadran 4
mi^2 = sa^2 + de^2
13^2 = sa^2 + (-5)^2
sa^2 = 169-25 = 144
sa = √144 = +12
cos a = sa÷mi = 12/13
tan = -de÷ sa = -5 ÷ 12
cosec = 1/sin = -13/5
sec = 1/cos = 13/12
cotan = 1/tan = -12/5

dicheck lgi yaa angka nya