此题结果有误吧?应该是-1/3吧?
其计算步骤如下:
∵ lim(a*b)=lima*limb,
∴将上式分成两部分lim(n+1)/n, 和lim[(2^n+(-3)^n)/(2^(n+1)+(-3)^(n+1)]
lim(n+1)/n∣n->∞=1;
lim[(2^n+(-3)^n)/(2^(n+1)+(-3)^(n+1)]∣n->∞ =-1/3
详细步骤如下:
[(2^n+(-3)^n)/(2^(n+1)+(-3)^(n+1)]=[(2^n+(-3)^n)/(2*(2^n+(-3)*(-3)^n],
分式上下同除于(-3)^n,则上式变为:
∴[(-2/3)^n+1)/(2*(-2/3)^n+(-3)*],
当n->∞时,(-2/3)^n ->0, ∴lim[(-2/3)^n+1)/(2*(-2/3)^n+(-3)*]=-1/3