Question

求函数y=3x²-1/x²+2的值域

Answer 1

【参考答案】

y=(3x²-1)/(x²+2)

y=[3(x²+2)-7]/(x²+2)

y=3-[7/(x²+2)]

∵ x²≥0

∴2+x²≥2, 0