f(x)在(0,+无穷)上递减,且f(2a^2+a+1)
问题描述:
f(x)在(0,+无穷)上递减,且f(2a^2+a+1)
答
f(x)在(0,+无穷)上递减,且f(2a^2+a+1)0,3a^2-4a+1>0再根据f(x)是递减函数的定义知有2a^2+a+1>3a^2-4a+1解上述三不等式由2a^2+a+1>0得a∈(-∞,+∞)由3a^2-4a+1>0得a∈(-∞,1/3)U(1,+∞)由2a^2+a+1>3a^2-4a+1得a...