1^3+3^3+5^3+……+99^3
=[99*(99+1)/2]^2
=9900^2/4
=24502500
2/3!+3/4!+4/5!+⋯⋯+99/100!
=(1/2!-1/3!)+(1/3!-1/4!)+(1/4!-1/5!)+⋯⋯+(1/99!-1/100!)
=1/2!-1/100!
(1)
syms k
a=symsum(k^3,1,99)
a =
24502500
(2)
double(symsum(k/factorial(k+1),2,99))
ans =0.5000