MatLab for loop help

• MATLAB
I have created a code in matlab that can plot the acceleration graph of the SVAJ diagram for 3 of the SCCA Family of Functions with a theta range from 0 to Beta. I cannot for the life of me, figure out what I am doing wrong, maybe some fresh eyes can help me. Ignore the 'trial', I'm trying to work for home, and didn't want to buy matlab. If you have the book Design of Machinery by Robert Norton 5th edition, its the figure on pg. 426. Thanks in advance to anyone that can help me
Code:
Trial>> b={.25, .25, .5}
b =
1×3 cell array
[0.2500]    [0.2500]    [0.5000]
Trial>> d={.25, .75, .5}
d =
1×3 cell array
[0.2500]    [0.7500]    [0.5000]
Trial>> for n=1:1:3
p=b(n)
z=d(n)
%Step 2: Create acceleration constant
Ca = 4*pi^2/((pi^2-8)*(p^2-z^2)-2*pi*(pi-2)*p+pi^2);
%zone 1 info%
x1 = 0:0.01:(p/2);
y1 = Ca*sin(pi*x1/p);
%zone 2 info%
x2 = p/2:0.01:(1-z)/2;
y2 = Ca;
%zone 3 info%
x3 = (1-z)/2:0.01:(1+z)/2;
y3 = Ca*cos(pi*(x3-(1-z)/2)/z);
%zone 4 info*
x4 = (1+z)/2 :0.01:1-p/2;
y4 = -Ca;
%zone 5 info%
x5 = (1-p/2):0.01:1;
y5 = Ca*sin(pi*(x5-1)/p);

x = [x1 x2 x3 x4 x5];
y = [y1 y2 y3 y4 y5];

plot(x,y)
end
p =
cell
[0.2500]

z =
cell
[0.2500]
Undefined operator '^' for input arguments of type 'cell'.   <---- this this the last error I received