I know that the exact solution of the main value of this integral is equal to zero:

$ int _ {- 1} ^ {1} int _ {- 1} ^ {1} frac {x ^ 2} { sqrt {1-x ^ 2}} frac { sqrt {1-y ^ 2}} {yx} dydx = 0 $

work:

```
To integrate[x^2/Sqrt[1 - x^2] Sqrt[1 - y^2]/ (y - x), {x, -1, 1}, {y, -1, 1},
PrincipalValue -> True]
```

But I want to do it numerically and it does not work:

```
NIntegrar[x^2/Sqrt[1 - x^2] Sqrt[1 - y^2]/ (y - x), {x, -1, 1}, {y, -1, 1}]
```

This is the error message returned:

How can I get *Mathematics* To solve this problem numerically?