Simple Integration

As follows:

圖片參考：http://i707.photobucket.com/albums/ww74/stevieg90/02-47.gif

(http://i707.photobucket.com/albums/ww74/stevieg90/02-47.gif)

2009-08-10 23:41:44 補充：
yes...再補充一下石石個做法:
Let u=1-x^2 , then du=-2xdx

∫x/√(1-x^2) dx
=∫x/√u (du/-2x)
=-1/2∫du/√u
=-1/2 (2√u)+c
=-√u+c
=-√(1-x^2)+c

or, you can set a variable u to be 1-x^2,
and this method is called "Substitution".

Stevie-G's method is an advanced substitution method