WBJEE · Maths · Basic of Mathematics
If \(2 \log (x+1)-\log \left(x^{2}-1\right)=\log 2\), then \(x=\)
- A only 3
- B \(-1\) and 3
- C only -1
- D 1 and 3
Answer & Solution
Correct Answer
(A) only 3
Step-by-step Solution
Detailed explanation
Hint: \(\log \left\{\frac{(x+1)^{2}}{x^{2}-1}\right\}=\log 2 \Rightarrow(x+1)^{2}=2\left(x^{2}-1\right) \Rightarrow x^{2}-2 x-3=0 \Rightarrow(x-3)(x+1)=0\) \(x=3 ; x \neq-1\)
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