Solving a Simple PDE: Understanding D/Dr and D/Dt

[quantum123]

How do you solve this simple PDE?
D/Dr (f) = D/Dt (f) ?
Pls don't just give me the final answer.

 

[J77]

Separation of variables.

 

[quantum123]

Not too sure how, can you help?

 

[d_leet]

Let f(r,t)=R(r)*T(t), substitute this into your originak equation, take the derivatives and separate the variables(Rs on one side of the equation and Ts on the other).