pembuktian dari sin a/1-cos a sehingga bisa menghasilkan cosec a + cot a

(sin a)/(1 - cos a)
= (sin a)/(1 - cos a) . (1 + cos a)/(1 + cos a)
= (sin a)(1 + cos a) / (1 - cos^2 a)
= (sin a)(1 + cos a) / (sin^2 a)
= (1 + cos a)/(sin a)
= 1/(sin a) + (cos a)/(sin a)
= cosec a + cot a

^2 = pangkat 2