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If 5f(x) + 4f\(\rm \left(\frac{1}{x}\right)\)= x2 – 2, ∀ x ≠ 0 and y = 9x2f(x), then y is strictly increasing in :
1
\(\rm \left(0,\frac{1}{\sqrt5}\right)\cup\left(\frac{1}{\sqrt5}, \infty\right)\)
2
\(\rm \left(-\frac{1}{\sqrt5},0\right)\cup\left(\frac{1}{\sqrt5}, \infty\right)\)
3
\(\rm \left(-\frac{1}{\sqrt5},0\right)\cup\left(0,\frac{1}{\sqrt5}\right)\)
4
\(\rm \left(-\infty,\frac{1}{\sqrt5}\right)\cup\left(0,\frac{1}{\sqrt5}\right)\)