Matlab gives back ''symsum'' formula but not a value

Question

Matas Rimkus 2022-5-19

回答： Walter Roberson 2022-5-19

The equations that I have to solve is

and

. I used these codes to solve them:

For equation no.1: F1=symsum(atan(pi/factorial(n)),n,0,Inf); Answer that matlab gives: symsum(atan(pi/factorial(n)), n, 0, Inf).

For equation no.2: F2=symsum(((-1)^n)*(sin(pi/(2^n))),n,1,Inf); Answer that matlab gives: symsum((-1)^n*sin(pi/2^n), n, 1, Inf).

If I delete atan and sin, matlab calculates F1 and F2 like it should, but with them, it only gives formulas back.

Answer 1

Walter Roberson 2022-5-19

Wolframalpha calculates the first sum numerically, not able to find a closed form for it.

What reason do you have to expect that a closed form exists?

symsum is for calculation of closed forms, not for numeric approximation.