1
y=(x-5²)(x+6)-6
y`=1*(x+6)+1(x-25)=x+6+x-25=2x-19=0
2x=19⇒x=8,5
_ +
---------------(8,5)-----------
min
ymin=y(8,5)=(8,5-25)(8,5+6)-6=-16,5*14,5-6=-245,25
2
y`=(-x²-400+2x²)/(x²+400)²=(x²-400)/(x²+400)²=0
x²=400⇒x=-20 U x=20
+ _ +
---------------(-20)---------------(20)----------------
min
ymin=y(20)=-20/800=-1/40
3
y`=(-x²-784+2x²)/(x²+784)²=(x²-784)/(x²+784)²=0
x²=784⇒x=-28 U x=28
+ _ +
---------------(-28)---------------(28)----------------
max
ymax=y(-28)=28/1568=1/56