MATLAB: My ‘For’ sequence is giving me “Array indices must be positive integers or logical values.”

Question

This is my code, can you tell me whats wrong with it, please?

a = 1;
pi = 3.14159265359;
b = (540/2)/1000; %mm 
rho = 8960; %kg/m3
c = 385; % J/(K·kg)
k = 400; % W/(K·m)
alpha = k/(rho*c);
y = input('y = ');
t = input('t=');
for i= 0:100
    x =((-1)^a(i))/((a(i)+(1/2))*pi)*e^(-(a(i)+(1/2))^2*pi^2*alpha*t/b^2)*cos(a(i)+(1/2))*pi*y/b
    x1 = 2*x 
end

Answer 1

Array index in MATLAB starts from 1 instead of 0.