Computing values of a formula

Hi,

I tried to solve this equation but apperantly my output is wrong, can you tell me what am I missing ?

clc
clear
close all
n=input('Please enter n : ')
x=input('Please enter x : ')
for k=0:floor(n/2); 
H=((-1)^k)*factorial(n)*(x^(n-2*k))/(2^k*factorial(k)*factorial(n-2*k));
H=H+((-1)^k)*factorial(n)*(x^(n-2*k))/(2^k*factorial(k)*factorial(n-2*k));
end
H

Answer 1

[Abhishek Tiwari]

Hi,

It appears that it is updating and doubling H with each cycle. So, the code you provided just doubles the result of the final step, i.e. when k = floor (n/2). Try initialising H before the loop and remove first line in the 'for' loop as demonstrated

clc
clear
close all
n = 10;
x = 2;
H = 0;
for k=0:floor(n/2); 
    H=H+((-1)^k)*factorial(n)*(x^(n-2*k))/(2^k*factorial(k)*factorial(n-2*k));
end
H

H = -2621

Answer 2

[Fatemeh Salar]

Dear @Abhishek Tiwari

Thanks for your help!