I attempted to solve a piecewise function in Maxima, but none of the solutions of the functions were returned:

```
piecewiseExample(x) := if (x < 5) then x*2 else x/2;
solve([piecewiseExample(x) = 4], [x]);
//result: [(if x<5 then 2*x else x/2)=4]
```

Is it possible for Maxima to obtain the solutions of an equation like this one?

Answer:

In simple cases you can solve every branch everywhere and filter solutions:

```
solve_and_filter(eq, var, p):= block([so: solve(eq, var), prederror: true],
sublist(so, lambda([c], p(rhs(c))))) $
pw_solve(pw, var):= map(lambda([L],
solve_and_filter(first(L), var, second(L))), pw) $
/* represent piecewise equation as a list of equation-predicate pairs
[ [eq1, pred1], [eq2, pred2], ... ] */
pw: [ [x*2 = 4, lambda([x], x< 5)],
[x/2 = 4, lambda([x], x>=5)]] $
/* solve every `eq' and filter solutions using `pred' */
pw_solve(pw, x);
```

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