# Question:how to use indets with conditions?

## Question:how to use indets with conditions?

Maple 2020

I am trying to learn how do somethings without using pattern matching and it is a struggle so far for me.

For an example, now I want to ask Maple to tell me if C[1] (which is a constant) exist in expression, as long as C[1] does not occur as argument to exp(....)

I'll explain why I want to do this and show small example and show how I ended solving it and ask if there is better way.

Given this expression (this can be result of dsolve for example. Made up here)

I just need to determine if the expression has C[1] anywhere, which is NOT an argument to exp(). In the above example, there is one.

The reason I want to find this, is that this is the constant of integration for first order ODE, and I want to repalce exp(C[1]) by constant C[1], but as long as there is no C[1] allready anywhere in expression on its, otherwise I need to introduce new constant C[2], which I do not want to do (since first order, should have only one constant of integration) and in this case will leave the expression as is and not try to simplify it.

But indets tells one that C[1] is there, not where. This is what I tried

```restart;
expr:=1/exp(z)*arcsinh(x*exp(C[1]))+x*C[1]*sin(exp(x))+3*exp(C[1]*y)*sqrt(sin(exp(3*C[1])));
indets(expr, specfunc(exp));
```

Now I can find if C[1] is argument to exp(....) from the above or not by more processing. (using applyrule or subsindets, etc...)

But first I still need to to determine if there is C[1] that exist anywhere else, as long it is not inside exp(.....).  If I do

`indets(expr, C[1]);`

But this does not tell me the information I want. It just says expression has C[1] somewhere.

I looked at evalindets and looked at applyrule and do not see how to use these to do what I want.

Basically I want to tell Maple this

indets(expr,C[1], conditional( C[1] is not anywhere inside exp(.....) ))

I can solve this using pattern matching. But I fnd Maple pattern matching awkaward to use sometimes and trying to learn how to do things without it.

So this is how I ended solving it. I replace all the C[1] inside exp(....) with ZZZ. Then use indets again to check if C[1] still there or not. This tells me what I want.

```restart;
expr:=1/exp(z)*arcsinh(x*exp(C[1]))+x*C[1]*sin(exp(x))+3*exp(C[1]*y)*sqrt(sin(exp(3*C[1])));
new_expr:=subsindets(expr, specfunc(exp), ()-> ZZZ);
if indets(new_expr, C[1])<>{} then
print("C[1] exist outside exp()");
else
print("C[1] does not exist outside exp()");
fi;
```

"C[1] exist outside exp()"

And

```restart;
expr:=1/exp(z)*arcsinh(x*exp(C[1]))+x*sin(exp(x))+3*exp(C[1]*y)*sqrt(sin(exp(3*C[1])));
new_expr:=subsindets(expr, specfunc(exp), ()-> ZZZ);
if indets(new_expr, C[1])<>{} then
print("C[1] exist outside exp()");
else
print("C[1] does not exist outside exp()");
fi;
```

"C[1] does not exist outside exp()"

is there a better way to do this?

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