x(1-3x)
=(1/3)3x(1-3x)
≤(1/3)[3x+(1-3x)]²/4
=(1/3)×(1/4)
=1/12
当3x=1-3x,x=1/6时不等式取等号
当x=1/6时,x(1-3x)取最大值1/12 x(1-3x)
=(1/3)3x(1-3x)
≤(1/3)[3x+(1-3x)]²/4
=(1/3)×(1/4)
=1/12
当3x=1-3x,x=1/6时不等式取等号
当x=1/6时,x(1-3x)取最大值1/12