Y=(x²+3)/(x+1)
D(y)=(-∞;-1) U (-1;∞)
y`=(2x²+2x-x²-3)/(x+1)²=(x²+2x-3)/(x+1)²=0
x²+2x-3=0
x1+x2=-2 u x1*x2=-3⇒x1=-3 u x2=1
+ _ +
----------(-3)-------------(1)--------------
max min
y(-3)=(9+3)/(-3+1)=-6
y(1)=(1+3)/(1+1)=2
x=-3∈(-∞;-1)⇒y∈(-∞;-6]
x=1∈(-1;∞)⇒y∈[2;∞)
E(y)∈(-∞;-6] U [2;∞)