Cao's theorem 3
From when x¡ú0 there are sin x=x, ex-1=x, ln(1+x)=x, (1+x)^§Ñ-1=§Ñx, we
can conclude follow theorem
1, ¡ßsin dx=dx

¡à ¡Òsin dx dx=¡Òdxdx=1

2, ¡ß edx-1=dx

¡à ¡Ò(edx-1)dx=¡Òdxdx=1

3, ¡ß ln(1+dx)=dx

¡à ¡Òln(1+dx)dx=¡Òdxdx=1

4, ¡ß (1+dx)^§Ñ-1=§Ñdx

¡à ¡Ò[(1+dx)^§Ñ-1]dx=¡Ò§Ñdxdx=§Ñ¡Òdxdx=§Ñ

These all can show even if a very tiny digital such as dx in the
integral formula, we cann't deal it with 0 and then calculate them
again, that is incorrect. Because even if a very tiny digital such as
dx¡ú0 , as after we calculate the integral formula , it is a number
that cann't be ignored. The 4 can explain it throughly.