已知函数F(X)=IN(X+1)-X/(A(X+1))在〔0,正无穷)为增函数,求A
问题描述:
已知函数F(X)=IN(X+1)-X/(A(X+1))在〔0,正无穷)为增函数,求A
答
f'(x)=1/(x+1)-1/(a(x+1))+x/(a(x+1)^2)
f'(0)=1-1/a>0
(a-1)/a>0
a>1或者a