lim(n+20)/(3n+13)其中n趋向无穷大,怎么样求得1/3?

lim(n+20)/(3n+13)其中n趋向无穷大,怎么样求得1/3? lim (n!+(n-1)!+(n-2)!+(N-3)!+⋯..+2!+1)/n!其中n→∞ lim(1+1/(n+2))^n其中n趋近无穷 lim(1+n/3)^(n+3)其中 n趋向于无穷 lim(n+3)(4-n)/(n-1)(3-2n) lim(n^3+n)/(n^4-3n^2+1) lim[(n+3)/(n+1))]^(n-2) 【n无穷大】 lim(2^n+3^n)^1 (n趋向无穷) lim(n+1)(n+2)(n+3)/3n^2,其中x趋于正无穷,求这个极限 lim根号n^2+n+1/3n-2 lim根号n^2+n+1/3n-2=? lim(根号下3n+n平方 -n)= 求lim n→∞ (1+2/n)^n+3 lim(n→∞)[1-(2n/n+3)] lim n->无穷大(2^n-1)/(3^n+1) lim(3^2n+5^n)/(1+9^n)=? lim(n→∞)(2n-1/n+3) lim[(4+7+...+3n+1)/(n^2-n)]=