y=(3x²-1)/(x²+2) 求值域y=(3x²-1)/(x²+2) 求值域_数学解答

y=(3x²-1)/(x²+2) 求值域
y=(3x²-1)/(x²+2) 求值域

人气：208 ℃　时间：2020-06-02 16:51:58

解答

y=(3x²+6-7)/(x²+2)
=3-7/(x²+2)
x²+2>=2
0<1/(x²+2)<=1/2
-7/2<=-7/(x²+2)<0
3-7/2<=3-7/(x²+2)<3+0
所以值域[-1/2,3)