求Y=I1+2xI+I2-xI的单调区间?

求Y=I1+2xI+I2-xI的单调区间?
求Y=I1+2xI+I2-xI的单调区间?

求Y=I1+2xI+I2-xI的单调区间?
由1+2x=0和2-x=0可得到三个取值区间：x

Y=|1+2x|+|2-x|
当x<-1/2,
y=-1-2x+2-x
=1-3x
当-1/2<=x<=2
y=1+2x+2-x
=3+x
当x>2
y=1+2x+x-2
=3x-1
所以
y=1-3x,x<-1/2
y=3+x,-1/2<=x<=2
y=3x-1,x>2
将这三个函数分...

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Y=|1+2x|+|2-x|
当x<-1/2,
y=-1-2x+2-x
=1-3x
当-1/2<=x<=2
y=1+2x+2-x
=3+x
当x>2
y=1+2x+x-2
=3x-1
所以
y=1-3x,x<-1/2
y=3+x,-1/2<=x<=2
y=3x-1,x>2
将这三个函数分别在坐标系上画出,可以知道:
单调递增区间为:[-1/2,正无穷)
单调递减区间为:(负无穷,-1/2)

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