计算:81^n×8^2n+1÷12^3n÷3^n
计算:n(n+1)(n+2)(n+3)+1
计算:(3a^n+2+6a^n+1-9^n)÷3a^n-1
证明不等式:(1/n)^n+(2/n)^n+(3/n)^n+.+(n/n)^n
计算1/(m-n)-1/(m+n)-2n/(m^2+n^2)-4n^3/(m^4+n^4)-8n^7/(m^8+n^8)
计算[5(m+n)2(m-n)]3÷【3(m+n)2(n-m)]2
计算(1×2×3+2×4×6+…+n×2n×3n)÷(1×3×5+2×6×10+…+n×3n×5n)
计算:C(1,n)+2C(2,n)+3C(3,n) + … + nC(n,n)
计算9^n*(1/27)^n+1*3^n+2
计算:(x^3)^n÷x^2n÷x^n-1
计算:b^(3n-1)/a^(2n-1)×c÷b^(3n-2)/a^2n
计算:(6a^n+2-9a^n+1+3a^n-1)÷3a^n-1
[3n(n+1)+n(n+1)(2n+1)]/6+n(n+2)化简