im stuck on these last two questions can anyone please help
find the range of these functions for XER
1) 1 / (x^2 + 2)
2)1 / (x^2 + 4x +5)
thanks
HI
(1) Let $\displaystyle y=\frac{1}{x^2+2}$
$\displaystyle yx^2+2y-1=0$
$\displaystyle b^2-4ac\geq 0$ since $\displaystyle x\in R$
$\displaystyle -4y(2y-1)\geq 0$
$\displaystyle 4y(2y-1)\leq 0$
so $\displaystyle y\in [0,\frac{1}{2}]$
The other one can be solved using this method too .