error in a loop

for n =1:N
for radius = 1:R  
% Random x & y numbers.
theta = rand(1,n)*(2*pi);
r = sqrt(rand(1,n))*radius;
end
x(n)= x1 + r.*cos(theta);
y(n)= y1 + r.*sin(theta);
end

plot(x,y,'.')

i am creating a random plot inside a circle using for command. i am having an error:

???  In an assignment  A(I) = B, the number of elements in B and
 I must be the same.

Error in ==> Q11 at 53
x(n)= x1 + r.*cos(theta);

how can i overcome this?

[Wayne King]

you do not show us what x1 and y1 are.

Answer 1

[Daniel Shub]

Just like the error says the number of elements in B and in I must be the same. For you, B is

x1+r.*cos(theta)

with the number of elements being equal to the number of elements in r and I is

n

with 1 element.

Are you sure you want

theta = rand(1,n)*(2*pi);
r = sqrt(rand(1,n))*radius;

and not

theta = rand*(2*pi);
r = sqrt(rand)*radius;