Question: Dot product with time derivative variable

I try to dot product 2 vector that contain time derivative

the answer should be v . u_rho = rhodot

but Maple doesn't give me a proper answer. What should i do?

kind regard

restart;

with(LinearAlgebra);

with(Typesetting);
Settings(typesetprime = true);
Settings(typesetdot = true);

v := <diff(rho(t), t)*cos(theta(t)) - rho(t)*diff(theta(t), t)*sin(theta(t)), diff(rho(t), t)*sin(theta(t)) + rho(t)*diff(theta(t), t)*cos(theta(t)), diff(z(t), t)>

u_rho := <cos(theta(t)), sin(theta(t)), 0>

v . u_rho

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