Incorrect render \( and \)

[nmalevich]

1. "Integral [\int_{a}^{b} x^2 ,dx] inside text" is rendered
2. "[\int_{a}^{b} x^2 ,dx]" is rendered
3. "Integral (\int_{a}^{b} x^2 ,dx) inside text" isn't rendered
4. "(\int_{a}^{b} x^2 ,dx)" isn't rendered