问题标题:
设函数f(x)=sinx-cosx+x+1(0<x<2π),求函数f(x)的单调区间与极值
问题描述:
设函数f(x)=sinx-cosx+x+1(0<x<2π),求函数f(x)的单调区间与极值
高欣回答:
f(x)=sinx-cosx+x+1
f'(x)=cosx+sinx+1=0
√2(sin(x+π/4))=-1
x+π/4=5π/4or7π/4
x=πor3π/2
f''(x)=-sinx+cosx
f''(π)=-10(min)
maxf(x)=f(π)=π+2
minf(x)=f(3π/2)=3π/2
单调区间
增加(0,π]or[3π/2,2π)
减小[π,3π/2]
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