matlab向量化编程问题

function y=concentration(d,m,t)
f=@(t)sqrt(t);
g=@(t)exp(-(1000-0.5t)^2/(450t));
r=@(m)repmat(m/20,1,58);
s=@(d)repmat(4d*pi.1.58)
y=r(M)/(f(t)*s(D)^0.5)*g(t);
th(d,m,t);
end
matlab初学，太迷茫了