[例3O|22:(2) dx dx 22 x ta x -a 解 ad(x a) =-arctan -+c x+a'dal(r a) d a -I 2(1-) arcsin -+C x 202//302021/1/30 7    + − −2 2 2 2 2 2 [ 3] (1) ; (2) ; (3) x a dx a x dx x a dx 例   + = + [1 ( ) ] ( ) (1) 2 2 2 2 a x a ad x a x a dx c ax a = arctan + 1 [ 解 ]  (1− 2 ) 2 2 ax a dx c ax ax d ax = + − =  ( ) arcsin 1 ( ) 1 2= −  2 2 (2) a x dx