不等式已知x满足2(log1/2x)^2+7log1/2x+3≤
已知x满足2(log1/2 x)^2+7log1/2 x+3≤0,求f(x)= ( log1/2 x/2)*(log2 x/4)的最值。 注： (log1/2 x)这里表示以1/2为底的x
2(logx)^2+7logx+3=<0 本题中省略底数1/2. --->(2logx+1)(logx+3)=<0 --->-3=-3/2=0=<(logx+3/2)^2=<9/4 --->-9/4=<-(logx+3/2)^2=<0 --->-2=<(logx+3/2)^2=<1/4 所以f(x)min=-2,(logx=-3/2--->x=2^(3/2)=22) f(x)max=1/4.(logx=-3--->x=2^3=8)