a+√(-x^2-4x)小于等于(4x/3)+1,求实数a的取值范围

问题描述:

a+√(-x^2-4x)小于等于(4x/3)+1,求实数a的取值范围

a+√(-x^2-4x)=a+√[4-(x+2)^2]不对,答案是小于等于-5f(x)=-√(-x^2-4x)+4x/3 f'(x)=(x+2)/√(-x^2-4x)+4/33(x+2)=4√(-x^2-4x)9(x^2+4x+4)=-16x^2-64x25x^2+100x+36=0(5x+10)^2=645x+10=-8x=-18/5-x^2-4x=-x(x+4)=36/25a+6/5