A Most General form of Canonical Transformation

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To find the general form of the canonical transformation given by Q = f(q) + g(p) and P = c[f(q) + h(p)], one must evaluate the Poisson brackets to ensure they satisfy the conditions {Q,Q} = {P,P} = 0 and {Q,P} = 1. This evaluation will help determine constraints on the functions f, g, and h. The challenge lies in applying these conditions to the general formula, as it does not yield the functions directly. It is suggested to explore specific relationships between (Q,P) and (q,p) to gain insights. This approach is essential for confirming the transformation's validity in Hamiltonian mechanics.
kolawoletech
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How do I go about finding the most general form of the canonical transformation of the form
Q = f(q) + g(p)
P = c[f(q) + h(p)]
where f,g and h are differential functions and c is a constant not equal to zero. Where (Q,P) and (q,p) represent the generalised cordinates and conjugate momentum in the new and old system
 
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Isn't this "homework" of some kind? You should post it in the Homework and Coursework section! Anyway, here's some hint:

I'd try to determine constraints on the functions by evaluating the Poisson brackets which must be
$$\{Q,Q\}=\{P,P \}=0, \quad \{Q,P \}=1$$
in order to have a canonical transformation.
 
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I am done all that with certain kinds of relationship between (Q,P) and (q,p) but I am unable to do so with this general formula that does not give the function itself
 
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