f(x)=2x-1g(x)=3-x则f[g(x)]g[f(x)]f[f(x)]g[g(x)]各怎么计算

来源:百度知道 编辑:UC知道 时间:2024/09/22 03:59:50

f(g(x)) = 2g(x) - 1 = 2(3-x) -1 = 5-2x
g(f(x)) = 3 - f(x) = 3 - (2x-1) = 4-2x
f(f(x)) = 2f(x) - 1 = 2(2x-1) -1 = 4x - 3
g(g(x)) = 3 - g(x) = 3 - (3-x) = x

f[g(x)]:
就是将g(x)=3-x看成t
所以f(t)=2t-1=2(3-x)-1=-2x+5

g[f(x)]=3-(2x-1)=-2x+4

f[f(x)]=2(2x-1)-1=4x-3

g[g(x)]=3-(3-x)=x

f[g(x)]=2*g(x)-1=5-2x
g[f(x)]=3-f(x)=4-2x

f[f(x)]=2f(x)-1=4x-3
g[g(x)]=3-g(x)=x