Jawabanmu

2014-05-20T11:36:38+07:00
Sin a ≡ 1/cosec a
sin a = 1/ \frac{1}{sin a}
sin a = sin a

cos a ≡ 1/sec a
cos a = 1/ \frac{1}{cos a}
cos a = cos a

NB :
cosec a = 1/sin a
sec a = 1/cos a