Find the domain of f(x) = sin(sqrt(1 - x²)) + sqrt(x + 2) + 1/log₁₀((x + 1)/x).
(0, 1]
[-1, 1]
(0, 1)
[-1, 0) U (0, 1]
Correct answer: (0, 1]
Solution
Intersect the conditions: x in [-1,1] from the first root, x >= -2 from the second, and (x+1)/x > 0 (i.e. x < -1 or x > 0) from the logarithm. The log is never 0 since (x+1)/x = 1 has no solution.