MATLAB: Help with a simple exercise

programming

In this exercise Im asked to show the Fibonacci numbers < 100… but when I run the program it shows me one > 100 (the 144), The 144 can't be there, what can I do? (Sorry for my english)

Here is what I got:

F(1)= 1; F(2)= 1;

n= 3; c= 0;

while c < 100;

    F(n)= F(n-1) + F(n-2);
    c= F(n);
    n= n+1;

end

Best Answer

Your code keeps running as long as c < 100, and goes ahead and computes and stores the next in sequence when that is true.

Suppose that it had generated 99 (I know it doesn't, but for the sake of explanation), then because 99 < 100, it would go on one more step and calculate the one after 99 -- which could not be < 100 considering there are no terms that involve adding 0 or negatives.

What you need to do is test for < 100 after you have done the calculation, but before you store into F, and do not store into F if it would be >= 100

Related Solutions

MATLAB: Fibonacci.m for Fibonacci Series

You function is not vectorized ... that is, it is not written to handle anything other than a scalar input. As written, you would need to call your function in a loop. E.g.,

n=1:10;
for k=1:numel(n)
    F(k) = Fibonacci(n(k));
end

The alternative would be to rewrite your function so that it can handle non-scalar inputs. E.g., suppose you did this:

m = max(n);
while i <= m

MATLAB: For loop for fibonacci series

In case of series, it is better to store each value. Please see below code that generatesa fibonacci sequence, and stores all the values in the variable"a";

a(1) = 0;
a(2) = 1;
n = input('Enter number of term desired ');
for i = 3:n
   a(i) = a(i-1)+a(i-2);
end

From here, if you want the n'th term, you do a(n), if you want the n-1, then you do a(n-1).

You method of trying to find the n-1 term can work with the following modification;

a = 0;
b = 1;
n = input('Enter number of term desired');
for i = 1:n-2 %term for n
    c = a + b;
    a = b;
    b = c;
end
a_n  = c; % nth term
a_n1 = a; %(n-1) term

Best Answer

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MATLAB: Fibonacci.m for Fibonacci Series

MATLAB: For loop for fibonacci series

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