Jawapan

2016-10-05T14:47:53+08:00
E/1 = 2f/1-f

2f = e-fe ( darab silang )
f = e-fe/2
2016-10-05T20:34:43+08:00
E=2f/1-f
e(1-f)=2f
e-ef=2f
2f+ef=e
f(2+e)=e
f=e/(2+e)