y'=2(x-1)(x-2)^3+(x-1)^2*3(x-2)^2=(x-1)(x-2)^2[2(x-2)+3(x-1)]=(x-1)(x-2)^2(5x-7)
y'>0时有:x7/5
y'
求单调区间 y＝（x－1）平方×（x－2）立方 ps：用求导
y'=2(x-1)(x-2)^3+(x-1)^2*3(x-2)^2=(x-1)(x-2)^2[2(x-2)+3(x-1)]=(x-1)(x-2)^2(5x-7)
y'>0时有:x7/5
y'