# Question:Why does isolate fail to isolate?

## Question:Why does isolate fail to isolate?

Maple 2015

In a recent answer I posted, I had a relation of the form

`I*Int(f(x), x) = something - 2*I*Int(f(x), x)`

and I wanted to isolate the term Int(f(x), x).
The function isolate failed to do it and I was forced to use some workaround to do the "isolation".

Trying to understand what happened here, it seems that isolate fails when the term to isolate is multiplied by the imaginary unit
Here are a few examples

 > expr := I*(Int(x^2*ln(-x+sqrt(x^2-1)), x)) = g(x) -(2*I)*(Int(x^2*ln(-x+sqrt(x^2-1)), x))
 (1)
 > # no isolation isolate(expr, lhs(expr))
 (2)
 > # isolation expr_1 := expand(expr / I) isolate(expr_1, lhs(expr_1))
 (3)
 > # no isolation neither, so the problem is not related to "Int" expr := I*diff(h(x), x) = g(x) -2*I*diff(h(x), x): isolate(expr, lhs(expr))
 (4)
 > # no isolation neither, so the problem comes from "I" expr := I*A = g(x) -2*I*A: isolate(expr, lhs(expr))
 (5)
 > # isolation (of course) expr := c*A = g(x) -2*c*A: isolate(expr, lhs(expr))
 (6)
 >