e+e 解 e +e dx ts∫d (er-e-r)211=arctan(e-e )+c 2(1+4) 解令1=23,a=d t In 2 +4)=](+t)h2in2(-1+r2 tIn 2 In 2 (2+ arctan 2) 四.求下列不定积分 解 99 xd(x-2)-9 x(x-2) 99(x-2 5.4 99xX-2)999×98(x-2)99.9」x(x-2)ax 5.4.3x2 99x-2)998(x-2)99.98.97x-2y99.9897.96(x-2) 5·4·3·2x 5·4·3.2 9098996.9x-2)-9.9.97.96.95(x-2y+c x√1+x tdt 解 令x=1/t 1⊥,4 tan u I rsec udu=- In tanu+ secu+ 五.求下列不定积分: x cos xdx 解.| x cos xdr x(+cos 2x)dx=x d sin 2x x +-xsin 2 in 2xdx1. Ú - + + dx e e e e x x x x 1 4 2 3 解. Ú Ú Ú = - + - + - = - + + = - + + - - - - - e e c e e d e e dx e e e e dx e e e e x x x x x x x x x x x x x x arctan( ) ( ) 1 ( ) 1 1 4 2 2 2 2 3 2. Ú 2 (1 + 4 ) x x dx 解. 令 x t = 2 , t ln 2 dt dx = c t t dt t t t t dx dt x x ˜ = - - + ¯ ˆ Á Ë Ê + = - + = + Ú Ú Ú ln 2 arctan ln 2 1 1 1 1 ln 2 1 2 (1 4 ) (1 )ln 2 2 2 2 2 = c x x - + + - (2 arctan 2 ) ln 2 1 四. 求下列不定积分: 1. Ú - dx x x 100 5 ( 2 ) 解. Ú Ú Ú - - + - - = - - = - - x x dx x x dx x d x x x 4 99 99 5 5 99 100 5 ( 2 ) 99 5 99 ( 2 ) ( 2 ) 99 1 ( 2 ) = Ú - - × × + ¥ - - - - x x dx x x x x 3 98 98 4 99 5 ( 2 ) 99 98 5 4 99 98 ( 2 ) 5 99 ( 2 ) = 96 2 97 3 98 4 99 5 99 98 97 96 ( 2 ) 5 4 3 99 98 97 ( 2 ) 5 4 99 98 ( 2 ) 5 99( 2 ) × × × - × × - × × - × - × - - - - x x x x x x x x c x x x + × × × × - × × × × - × × × × - × × × - 95 94 99 98 97 96 95 ( 2 ) 5 4 3 2 99 98 97 96 95 ( 2 ) 5 4 3 2 2. Ú + 4 x 1 x dx 解. Ú Ú Ú Ú + = - + = - + - = + 2 2 2 4 4 4 2 4 2 1 ( ) 1 1 1 1 1 1 / 1 t dt t tdt t t t dt t x t x x dx 令 c x x du u u c u u t u + + = - = - + + = - Ú 2 2 4 2 1 ln 2 1 ln | tan sec | 2 1 sec sec 2 1 令 tan 五. 求下列不定积分: 1. Ú x xdx 2 cos 解. Ú Ú Ú x xdx = x + x dx = x + xd sin 2x 4 1 4 1 (1 cos 2 ) 2 1 cos 2 2 Ú = x + x x - sin 2xdx 4 1 sin 2 4 1 4 1 2