Hi Keerthana,
It is because the if condition placed is wrong, and always fx3 is getting 0, therby making only a single point.
Updated the code to match what you are trying below:
for a=1:2:4
x=linspace(-5,5,300);
fx3 = zeros(1,length(x)); % Intialize the value to zeros
xPositive = x(x>=0); % Find the values of x which are greater than or equal to 0
fx3(x>=0)=(xPositive/a^2).*exp((-1/2)*(xPositive/a).^2); % Update the value of fx3, when x >= 0
figure(6);
plot(x,fx3);
hold on
end
hold off
Hope this helps.
Regards,
Sriram
