若F(x)是(x)的原函数,则fxtx=[F(x)=F(b)-F(a) 例3计算[x2k 解2h=号=号P=30 例4计算广1x 解 C 1+r2==arctan 3-arctan( 丌丌、7 ( 412 首页上页返回 页结束铃首页 上页 返回 下页 结束 铃 若 F(x)是 f(x)的原函数, 则 f (x)dx [F(x) ] F(b) F(a) b a b a = = −  . 解 解 例3 例 1 计算 1 0 2 x dx . 3 1 0 3 1 1 3 1 ] 3 1 [ 1 3 3 0 3 1 0 2 = =  −  =  x dx x . 例 例 2 4 计算 2 3 1 1 x dx +  − . 3 2 1 3 1 [arctan ] 1 − − = +  x x dx =arctan 3−arctan(−1)    12 7 ) 4 ( 3 = − − = . 3 1 0 3 1 1 3 1 ] 3 1 [ 1 3 3 0 3 1 0 2 = =  −  =  x dx x . 3 1 0 3 1 1 3 1 ] 3 1 [ 1 3 3 0 3 1 0 2 = =  −  =  x dx x . 3 2 1 3 1 [arctan ] 1 − − = +  x x dx =arctan 3−arctan(−1) 3 2 1 3 1 [arctan ] 1 − − = +  x x dx =arctan 3−arctan(−1) 下页