### Related

unsum(1/2^x,x);

Calculate

? unsum;

Calculate

f(n) := n^2;

f(8);

unsum (f, n);

Calculate

##### unsum

unsum(90/(x*x-5*x+4),x);

Calculate

f(n) := n^2;

f(8);

unsum (f, 10);

Calculate

unsum(1/2^x,x);

Calculate

? unsum;

Calculate

f(n) := n^2;

f(8);

unsum (f, n);

Calculate

##### unsum

unsum(90/(x*x-5*x+4),x);

Calculate

f(n) := n^2;

f(8);

unsum (f, 10);

Calculate

### unsum

Run Example
```(%i1)sum (n^4*4^n/binomial(2*n,n), n, 0, inf);
inf
====        4  n
\          n  4
(%o1)                        >    ----------------
/     binomial(2 n, n)
====
n = 0
(%i2)  unsum (%, n);
(%o2)                                  0
(%i3)  unsum (prod (i^2, i, 1, n), n);
n - 1
/===\
! !   2
(%o3)                     ( ! !  i ) (n - 1) (n + 1)
! !
i = 1
(%i4)  nusum (%, n, 1, n);
(%o4)            ```
Run Example
```simplify_sum(sum(1/(k^2), k, 1, inf));
inf
====
\     1
(%o1)                       simplify_sum( >    --)
/      2
====  k
k = 1
(%i2)  nusum ((binomial(n,k))^2/binomial(2*n,n), n, 0, n);
n
====          2
\     binomial (n, k)
(%o2)                        >    ----------------
/     binomial(2 n, n)
====
n = 0
(%i3)  unsum (%, n);
(%o3)                                  0
(%i4)  unsum (prod (i^2, i, 1, n), n);
n - 1
/===\
! !   2
(%o4)                     ( ! !  i ) (n - 1) (n + 1)
! !
i = 1
(%i5)  nusum (%, n, 1, n);
(%o5)            ```
Run Example
```f(n) := n^2;
2
(%o1)                             f(n) := n
(%i2) f(8);
(%o2)                                 64
(%i3) unsum (f, 10);
(%o3)                                  0
(%i4) ```

Help for Unsum