2x2+3 例5求lim x→0 3x2+1 xBr+破,3 解lim 2x2+3 x→0 3+ 2 3 im(2+,) x→00 im(3+2) 3例5 求 . 3 1 2 3 lim 2 2 + + → x x x 解 3 1 2 3 lim 2 2 + + → x x x 2 2 1 3 3 2 lim x x x + + = → ) 1 lim(3 ) 3 lim(2 2 2 x x x x + + = → → . 3 2 =