f(x)=|x-1|,g(x)=x2+2x+1,求f(x)+g(x)的单调增区间

问题描述:

f(x)=|x-1|,g(x)=x2+2x+1,求f(x)+g(x)的单调增区间

f(x)=|x-1|
g(x)=x^2+2x+1=(x+1)^2
x>=1 f(x)+g(x)=x-1+(x+1)^2=x^2+3x=(x+3/2)^2-9/4
所以在x>-3/2上面增 (因为x>=1 )所以x>=1 上增
x=-1/2上面增 (因为x