旧版凤凰血国语中字:F(x)是定义在R上的偶函数,其图象关于X=1对称,对任意X1,X2属于【0,0.5】都有F(X1+X2)=F(X1)+F(X2)

来源:百度文库 编辑:高校问答 时间:2024/05/10 07:49:40
1. 设F(1)=a,求F(0.5) F(0.25)
2. 证明F(X+2)=F(X)

很简单啊。
f(1/2) + f(1/2) = f(1/2+1/2) = f(1) = a
f(1/2) = a/2
同理f(1/4) = a/4

偶函数:f(-x) = f(x)
关于x=1对称:f(1+x) = f(1-x)
f(x+2) = f(1+x+1) = f[1-(x+1)] = f(-x) = f(x)

解:
∵f(x)是定义在R上的偶函数
∴x = 0是y = f(x)对称轴;
又∵f(1+x)= f(1-x)
∴x = 1也是y = f (x) 对称轴。
故y = f(x)是以2为周期的周期函数,
∴f (8.6 ) = f (8+0.6 ) = f (0.6 ) = f (-0.6 ) = 0.3

解:
∵f(x)是定义在R上的偶函数
∴x = 0是y = f(x)对称轴;
又∵f(1+x)= f(1-x)
∴x = 1也是y = f (x) 对称轴。
故y = f(x)是以2为周期的周期函数,
∴f (8.6 ) = f (8+0.6 ) = f (0.6 ) = f (-0.6 ) = 0.3