求极限,当x趋向于5时,(根号下2x-1,再减3)/根号下x-4,再减1.

问题描述:

求极限,当x趋向于5时,(根号下2x-1,再减3)/根号下x-4,再减1.

lim(x→5)(√(2x-1)-3)/(√(x-4)-1)=lim(x→5)(2x-1-9)/(√(2x-1)+3)*(√(x-4)+1)/(x-4-1)=lim(x→5)2(x-5)/(x-5)*(√(x-4)+1)/(√(2x-1)+3)=2*(1+1)/(3+3)=2/3