Buktikan identitas trigonometri berikut

Buktikan identitas trigonometri berikut

$frac{ sin(A) }{1 + cos(A) } + frac{ sin(A) }{1 - cos(A) } = \ \ frac{ sin(A)(1 - cos(A) ) + sin(A) (1 + cos(A)) }{(1 + cos(A) )(1 - cos(A)) } = \ \ frac{ sin(A) - sin(A) cos(A) + sin(A) + sin(A) cos(A) }{1 - cos^{2}(A ) } = \ \ frac{2 sin(A) }{ { sin }^{2} A} = frac{2}{ sin(A) }$