求最值1、y=5+根号2x^2-10x+3 2、y=(x-1)/(x+2) x属于[-1,3]

求最值1、y=5+根号2x^2-10x+3 2、y=(x-1)/(x+2) x属于[-1,3]
求最值1、y=5+根号2x^2-10x+3 2、y=(x-1)/(x+2) x属于[-1,3]

求最值1、y=5+根号2x^2-10x+3 2、y=(x-1)/(x+2) x属于[-1,3]
∵根号(2x^2-10x+3)=根号[2(x-2.5)^2-9.5]≥0
y=5+根号(2x^2-10x+3）≥5,最小值5
y=(x-1)/(x+2) =(x+2-3)/(x+2)=1 - 3/(x+2)
x+2单调增
3/(x+2)单调减
1 - 3/(x+2)单调增
y=(x-1)/(x+2)=1 - 3/(x+2)单调增
x=-1时,最小值1-3/(-1+2)=-2
x=3时,最大值1-3/(3+2)=2/5