Найти границу lim (sqrt (1-x) -sqrt (1+x) / (2x)

lim (sqrt (1-x) -sqrt (1+x) / (2x)=lim (sqrt (1-x) -sqrt (1+x)*(sqrt (1-x)+sqrt (1+x) / (2x*(sqrt (1-x)+sqrt (1+x)=-lim (2x/2x*(sqrt (1-x)+sqrt (1+x)=-lim (1/ (sqrt (1-x)+sqrt (1+x) pri x->0: -lim (1/ (sqrt1+sqrt1)=-1/2=-0,5.