The question asks if both of these integrations can be correct and why/why not?
a) ∫dx / √1 - x² = -∫-dx/ √1-x² = -cos‾¹x + C
b) ∫dx / √1 - x² = ∫-du/√(1 - (-u)²) x = -u dx= -du
= ∫-du/√1- u²
= cos‾¹u + C u= -x
= cos‾¹(-x) + C
Both of them are correct.
Actually, (a) and (b) obtain the ...
This shows how to determine if given integrals are correct.