Question

已知二次函数f(x)=ax^2+bx+c(a,b,c∈R,a≠0),f(-2)=f(0)=0,f(x)的最小值为-1.

求（1）函数f(x)的解析式。
（2）设g(x)=f(-x)-mf(x)+1，若g(x)在[-1,1]上是减函数，求实数m的取值范围。
(3)设函数h(x)=log2[n-f(x)]，若此函数在定义域范围内不存在零点，求实数n的取值范围。

Answer 1

解：

(1)

f(-2)=f(0)=0

∴可设f(x)=a(x+2)x,对称轴x=-1,顶点纵坐标是f(-1)=-a=-1,得a=1,

∴f(x)=x²+2x,

(2)

g(x)
=x²-2x-mx²-2mx+1
=(1-m)x²-2(1+m)x+1

当m=1时，g(x)=-4x+1,满足题意，

当m>1时，需(1+m)/(1-m)<-1,恒成立，

当m<1时，需(1+m)/(1-m)>1,解得0<m<1,

综上，m的取值范围是[0, ∞),

(3)

h(x)=lg2(-x²-2x+n),

定义域是-x²-2x+n>0,有解的条件是n>-1,

-x²-2x+n最大值是n+1，

不存在零点说明n+1<1,即n<0,

所以-1<n<0,

完毕！

谢谢！

Answer 2

,air max tn

Travel with Change in Peru

It is important to travel with change in Peru. The sol is the official currency of Peru. While the US dollar is widely accepted in the larger hotel and supermarket chains, and just about every travel agency, the sol is used almost everywhere else. Many things are very cheap in Peru. Rarely does a small corner store see a 100 soles bill. It would be in your best interest to keep a healthy amount of small coins with you when you travel in Peru, especially if you will be doing any traveling off the beaten path.Denominations less than 1 sol are called centimos. It is advisable to keep several 10, 20 and 50 centimos coins with you. Also include 1,air max tn, 2 and 5 soles coins. Your won’t need too many bills unless you are paying for a hotel,nike tn, a tour, a flight or an expensive place to eat.Some small stores and towns simply won’t have change for higher denominations. Some people will have change, but will tell you they don’t in hopes of keeping the extra amount. Never pay for a bus or taxi ride with anything but exact change. They are notorious for not giving the correct amount back,air jordan, especially to tourists. Travel with change in Peru helps you prevent rip-offs and losing too much money in case of pick-pocket theft. It is not only desirable,air max, but necessary to have coins on hand in many places of the country. There is nothing quite like the feeling of having several 100 soles bills in your pocket only to find that you can’t pay for a hostel that costs just 10 soles because the staff doesn’t have change.

Travel with Change in Peru

More topics related to article：

The Immune Response And The Allergic Reaction_922

Use your maiden name

Make the Most of Your Portugal Surfing Holidays_2728

Answer 3

k