4.已知函数y=loga(x+3)-1(a>0,且a≠1)的图象恒过定点A,若点A在直线mx+ny+1=0上,其中mn>0,则m2+$\frac{1}{4}$n的最小值为$\frac{3}{16}$.
3.定义在R上的函数f(x)满足(x-1)f′(x)≤0,且f(-x)=f(2+x),当|x1-1|<|x2-1|时,有( )
| A. | f(2-x1)≥f(2-x2) | B. | f(2-x1)=f(2-x2) | C. | f(2-x1)>f(2-x2) | D. | f(2-x1)≤f(2-x2) |
17.已知函数f(x)=ex-mx+1的图象为曲线C,若曲线C存在与直线y=x垂直的切线,则实数m的取值范围为( )
| A. | m≤1 | B. | m≤-1 | C. | m>1 | D. | m>-1 |
16.
已知f(x)=Asin(ωx+φ)(A>0,ω>0,|φ|<$\frac{π}{2}$)的部分图象如图所示,且满足f(0)=f($\frac{π}{3}$)则下列说法正确的是( )
0 233577 233585 233591 233595 233601 233603 233607 233613 233615 233621 233627 233631 233633 233637 233643 233645 233651 233655 233657 233661 233663 233667 233669 233671 233672 233673 233675 233676 233677 233679 233681 233685 233687 233691 233693 233697 233703 233705 233711 233715 233717 233721 233727 233733 233735 233741 233745 233747 233753 233757 233763 233771 266669
| A. | f(x)的最小正周期为2π | B. | f(x)在[0,$\frac{π}{4}$]上是增函数 | ||
| C. | f(x)的图象关于直线x=$\frac{5}{6}$π对称 | D. | f($\frac{2π}{3}$)=-2 |