lim(x->∞) [( x-1)/(x+2)]^(3x)=lim(x->∞) [1 +1/(x+2) ]^(3x)let1/y = 1/(x+2)x= y-2x->∞,y->∞lim(x->∞) [1 +1/(x+2) ]^(3x)=lim(y->∞) [1 +1/y ]^(3y-6)=e^3
x趋于0吗？那就x=0代入=(-1/2)^0=1
