error using multiplication, incorrect dimensions

I get an error that says error using * in lines 18 and 19, I can't quite seem to figure out where the correction is to be! anything helps! thanks

delta = 0.05; 
p = 0.85; 
v = 0.05; 
y = [0 0.50 2.5]; 
u = 0.02; 
I = 6000000;
t = [0 10 100]; 
c0 = 95000000;
n0 = 112000000; 
e = 1; 

theta = y + u + v + delta; 
s = p + theta + u; 
b = p*v + p*delta + p*u + u*theta; 
a = 2*p + u; 
n1 = 1/2*(s - sqrt(s.^2 - 4*b));
n2 = 1/2*(s + sqrt(s.^2 - 4*b));
k1 = ((b*(p+theta-n2)*c0+I*(a*n2-b)-(p*b*n0))/(b*(n1-n2))); 
k2 = ((-b*(p+theta-n1)*c0+I*(b-a*n2)-(p*b*n0))/(b*(n1-n2)));

 
c_t = k1*e.^(-n1*t) + k2*e.^(-n2*t)+(a/b)*I; 

plot (t, c_t);

Answer 1

[James Tursa]

There are vectors in those equations, so maybe you just need to use element-wise operations:

k1 = ((b.*(p+theta-n2).*c0+I.*(a.*n2-b)-(p.*b.*n0))./(b.*(n1-n2))); 
k2 = ((-b.*(p+theta-n1).*c0+I.*(b-a.*n2)-(p.*b.*n0))./(b.*(n1-n2)));