How do I change the sign without altering the other and how can I do the factorial denominator? 1-1/3!+1/5!-1/7!+... and perform the sum?

disp('serie 4: 1-1/3!+1/5!-1/7!+...' )
n=input('Enter a number: ');
sum=0;
for j=1:2:n
    sum = sum + 1/j;
end
disp('the sum is: ')
disp(sum)

I don't know how to do that series please someone help me if you can.

[the cyclist]

This is a pretty basic question, so it's difficult to know what to assume about your MATLAB knowledge, and what to suggest. What have you tried?

Do you know how to program a for loop, or a while loop?

Is this a homework assignment?

[Becca]

I try with for but it doesn't work, I don't know how to make the denominator factorial. it is a review exercise for a lesson

[the cyclist]

Try googling matlab factorial.

:-)

Also, if you post your code, folks can make more specific suggestions. (You can use the paperclip icon in the INSERT section of the toolbar.)

[Walter Roberson]

hint: (-1) to an integer power.

Answer 1

[David Hill]

disp('serie 4: 1-1/3!+1/5!-1/7!+...' )
n=input('Enter a number: ');
Sum=0;
for j=1:n
    Sum = Sum + (-1)^(j+1)/factorial(2*j-1);
end
disp('the sum is: ')
disp(Sum)

alternatively, no for-loop needed.

Sum=sum((-1).^(0:n-1)./factorial(1:2:2*n));