using the while command

By using the while command, I have to determine the number of terms needed so that the product 2x4x6x8...x2n exceeds a given number N (input by the user). The following is what I tried but it doesn't seem to work.

function y=question2(i,n);
N=input('Enter number N: ')
for i=1:1:n
question2=2*(i)
while question2<=N
   question2=question2*(i+1)
    display(n)
end
end

Thanks in advance.

Answer 1

[Azzi Abdelmalek]

You should use only while loop (remove the for loop), then increment the variable i inside the while loop (i=i+2).

[francesca]

Thanks very much for your help and for your time.

Answer 2

[David Sanchez]

Hello Francesca, firstly, why do you use "i" as a input variable? Since you use "i" as index within the for-loop, the input "i" will not be used. (advice: try to avoid using "i" as loop index to avoid confusing with imaginary unit) Second: do not forget to add semicolons (;) at the end of each line, it will produce a cleaner result, unless you want lots of useless information on the command windows. Before attempting anything, try to determine what your input variables will be.

Answer 3

[David Sanchez]

try this code, but remember that we are not here to do your homework.

N = input('Enter number N: ');
n = 2;
r = 2;
count = 0;
while r < N
    count = count + 1;
    n = n + 2;
    r = 2*n;
end
disp(count)

[francesca]

Thanks very much for your help and for your time.