Mathematics

Mathematics

Problem

If 5f(x)+4f(1x)=x2−2,∀x≠05f(x) + 4f(\frac{1}{x}) = x^2 - 2, \forall x \neq 0 and y=9x2f(x)y = 9x^2 f(x) , then yy is strictly increasing in: ![](![](https://storage.googleapis.com/diraq-contents/homework-question-parsing/marker/20260106T182719Z/cfffd1f08c4f4f9a8fc99c99b28937d8/30a26f2d17ca95672702bf50fb4f0242_img.jpg)) A (0,15)∪(15,∞)(0, \frac{1}{\sqrt{5}}) \cup (\frac{1}{\sqrt{5}}, \infty) B (−15,0)∪(15,∞)(-\frac{1}{\sqrt{5}}, 0) \cup (\frac{1}{\sqrt{5}}, \infty) C (−15,0)∪(0,15)(-\frac{1}{\sqrt{5}}, 0) \cup (0, \frac{1}{\sqrt{5}}) D (−∞,15)∪(0,15)(-\infty, \frac{1}{\sqrt{5}}) \cup (0, \frac{1}{\sqrt{5}})

Browse the problem library