已知函数f(x)=[(x-1)/(x+1)]²,(x>1);若不等式(1-√x)fֿ¹(x)>a(a-√x)对一切x∈[1/4,1/2]恒成立,求
a的取值范围
解:y=[(x-1)/(x+1)]²,定义域:x>1;值域0
∵x>1,∴x={-2(y+1)-√[4(y+1)²-4(y-1)²]}/[2(y-1)]=[-2(y+1)-4√y]/[2(y-1)]=-(y+2√y+1)/(y-1)
=-(√y+1)²/(√y+1)(√y-1)=-(√y+1)/(√y-1)=(1+√y)/(1-√y) (0
故fֿ¹(x)=(1+√x)/(1-√x),(0
即有a²-1-(a+1)√x<0对一切x∈[1/4,1/2]恒成立;
(a+1)(a-1)-(a+1)√x=(a+1)(a-1-√x)<0
故得-1即-1
看不懂啊
你先把题目写清楚吧
用公式编辑器写清楚吧