This is a ‘Yes-No’ type of DS question. To know whether |x| < 1, we need to find if -1<x<1, since this is the range that satisfies |x| < 1.
From statement I alone, \(x^2\) < 1. In questions on inequalities, keep the RHS as ZERO and express the LHS as a product or a quotient. This helps you to identify the signs on the left side.
Taking 1 to the LHS, we have \(x^2\) – 1 < 0. The LHS can be simplified as (x-1)(x+1) < 0. The above inequality is satisfied by the range -1<x<1. This means that |x| < 1. We can answer the question with a definite YES.
Statement I alone is sufficient. Answer options B, C and E can be eliminated. Possible answer options are A or D.
From statement II alone, |x| < \(\frac{1 }{ x}\). We can substitute the values of |x| and simplify the inequalities in a similar way that we did in the first statement.
|x| = x when x≥0. Substituting this value of |x|, we have x<\(\frac{1}{x}\), which can be simplified as x-(\(\frac{1}{x}\)) < 0.
Therefore, \(\frac{(x^2 – 1)}{ x}\) < 0. Since we have taken x>0, \(x^2\)-1<0. The range that satisfies \(x^2\) – 1< 0 is -1<x<1. But since x>0, the effective range would be 0<x<1. For this range of x, is |x| < 1? Yes, it is.
|x| = -x when x<0. Substituting this value of |x|, we have -x < (\(\frac{1}{x}\)), which can be simplified as -x-(\(\frac{1}{x}\)) < 0.
Therefore, \(\frac{(-x^2 – 1) }{ x}\) <0. Since we have taken x<0, -(\(x^2\)+1) has to be positive, which means \(x^2\)+1 has to be negative i.e. \(x^2\)+1<0 or \(x^2\)<-1. \(x^2\) can never be less than -1, therefore we can conclude that we cannot take x<0.
So, from statement II alone, we know that |x| < 1. Statement II alone is sufficient. Answer option A can be eliminated.
The correct answer option is D.
Hope that helps!