Give an example of a first order differential equation that meets each of the following: (a) Can be solved with separation of variables but not with any of the other three methods. (b) Can be solved with the method of integrating factors but not with any of the other three. (c) Can be solved a Bernoulli transformation but not with any of the other three. (d) Can be solved with either separation of variables or the method of integrating factors. (e) Can be solved with either integrating factors or MUC. (f) Cannot be solved with any of our four techniques.