Since the system is linear in P(t) we can use the principle of superposition to calculate the response to P(t) in terms of the response to individual unit steps [ ] 0 0 0 1 1 ( ) ( ) ( ) ( ) ( ) ( ) ( ) i i i i T t T t P t P P t τφτττφτ ∞ ...
Related to this work with partial differential equations was his discovery of a solution to the problem of distribution of heat in a solid with a variable boundary temperature, now known as Duhamel’s principle. Duhamel also taught at the École Normale Supérieure and at the Sorbonne (both ...