更新时间2021-10-29 22:07:12
lim(x→1) √{ ( x² - 1 )/[ 2( x - 1 ) ] }
= lim(x→1) √{ ( x - 1 )( x - 1 )/[ 2( x - 1 ) ] }
= lim(x→1) √{ ( x + 1 )/2 }
= ( 1 + 1 )/2
= 1 。
解一
lim【x→1】√{(x²-1)/[2(x-1)]}
=lim【x→1】√[(x+1)/2]
=√[(1+1)/2]
=1
解二
lim【x→1】√{(x²-1)/[2(x-1)]}【x=y+1】
=lim【y→0】√{[(y+1)²-1]/(2y)}
=lim【y→0】√[(y+2)/2]
=(0+2)/2
=1