Could anyone help me to solve the error in the following code

code:

syms n k
n=4
k=0
symsum(nchoosek(n,k),k,0,n)

If i run the code it gives error stating Undefined function 'symsum' for input arguments of type 'double'.

Could anyone help me how to overcome it.

Answer 1

[Walter Roberson]

>> syms n k
>> symsum(nchoosek(n,k),k,0,n)
ans =
2^n
>> subs(ans, n, 4)

[jaah navi]

ok.thanks.the above command executes when n=4,could you please help me how to execute using different values on n say for example n=4,5,6,7. I tried with the following command for n=3,5,7 k=0 syms n k symsum(nchoosek(n,k),k,0,n) subs(ans, n, (3,5,7)) end but unable to get the result.Could you please help me on this.

[Walter Roberson]

syms n k
f = symsum(nchoosek(n,k),k,0,n);
subs(f, n, [4 5 6 7])

[jaah navi]

ok.thanks.

Answer 2

[GK]

You need to have Symbolic Math Toolbox. Please check the link Symsum undefined function error.

[jaah navi]

ok.Is there anyother way to rewrite the above commands as there is no Symbolic Math Toolbox.

[GK]

Could you share your code or example of it. Also I want to know, if its series is finite or infinity?

[Walter Roberson]

You would not have been able to use

syms n k

without the Symbolic Math toolbox -- not unless you happened to have Maple installed instead.