Source: Extra Practice

Solve the inequality: log⁡x2(x+2)<1\log_{x^2} (x+2) < 1.

Options

Option A is correct

x∈(−2,−1)∪(−1,0)∪(0,1)∪(2,∞)x \in (-2, -1) \cup (-1, 0) \cup (0, 1) \cup (2, \infty)

Option B

x∈(−1,1)∪(2,∞)x \in (-1, 1) \cup (2, \infty)

Option C

x∈(−2,∞)x \in (-2, \infty)

Option D

x∈(2,∞)x \in (2, \infty)

Explanation

First, find constraints for base and argument:

  1. Base x2>0x^2 > 0 and x2≠1  ⟹  x≠0x^2 \neq 1 \implies x \neq 0 and x≠±1x \neq \pm 1.
  2. Argument x+2>0  ⟹  x>−2x + 2 > 0 \implies x > -2.

Now, analyze the inequality in two cases based on the value of the base x2x^2:

Case 1: 0<x2x2  ⟹  x2−x−2<0  ⟹  (x−2)(x+1)<0  ⟹  −1<x1  ⟹  x∈(−∞,−1)∪(1,∞)0 < x^2 x^2 \implies x^2 - x - 2 < 0 \implies (x-2)(x+1) < 0 \implies -1 < x 1 \implies x \in (-\infty, -1) \cup (1, \infty). Since the base is greater than 1, the inequality sign remains the same: x+20  ⟹  x2x+2 0 \implies x 2. Intersection with x>−2x > -2 and base constraints for Case 2 yields: x∈(−2,−1)∪(2,∞)x \in (-2, -1) \cup (2, \infty).

Combining both cases, we get: x∈(−2,−1)∪(−1,0)∪(0,1)∪(2,∞)x \in (-2, -1) \cup (-1, 0) \cup (0, 1) \cup (2, \infty).