记函数f(x)=更号2-(x+3/x+1)的定义域为A,g(x)=lg[(x-a-1)(2a-x)](a<1)的定义域为B.求:若B包含于A,求实数a的取值范围.
热心网友
f(x)=[2-(x+3)/(x+1)]---2-(x+3)/(x+1)=0---[2(x+1)-(x+3)]/(x+1)=0---(x-1)/(x+1)=0----1A=(-1,1]g(x)=lg[(x-a-1)(2a-x)] (a-(x-a-1)(x-2a)0 [a2a2aB=(2a,a+1)因为B包含于A，所以 2a=-1; & a+1=-1/2=