If S is the interval such that f(x) = 8x2 – ln |x| increases in S then S contains
Answer & explanation
Correct answer: option 1
Here $f'(x)= 16 x-\frac{1}{x} =\frac{16}{x}(x^2-\frac{1}{16})$.
For an increasing function, $f'(x)>0⇒\frac{1}{x}(x-\frac{1}{4})(x+\frac{1}{4})>0$.
Hence (A) is the correct answer.