求函数y=X-3X-1的单调区间和极值

问题描述:

求函数y=X-3X-1的单调区间和极值

f(x) = x - 3x - 1 令f'(x) = 3x - 3 = 0,得x = -1或1 f(x)max = f(-1) = 1,f(x)min = f(1) = -1 单调增区间为(-∞,-1)∪(1,+∞),单调增区间为[-1,1].