x2n-1 2n-1 s(x)= 02n x22t)=∑,n) n=1 2 hE 2 庄=(∑,y= H-=1 x 2-x x2+2 2-x2)(2-x2)2 王mxx)==3,故应2n1=3 x2+2 = 上页  = −  − = 1 0 2 2 ) 2 2 1 ( ) ( n x n n x dx n s x   = − =  1 2 1 ) 2 ( n n n x ) ) 2 ( 1 ( 1 2 =    n= x n x ) 2 1 ( 2 2  − =  x x x ) 2 ( 2  − = x x , (2 ) 2 2 2 2 x x − + = 2 2 2 1 (2 ) 2 lim x x x − + = → − lim ( ) 1 s x x→ − = 3, 3. 2 2 1 1 = −   n= n n 故