f(x)+g(x)=(x+1)^2
f(-x)+g(-x)=[(-x)+1]^2=(x-1)^2
[f(x)+g(x)]+[f(-x)+g(-x)]=(x+1)^2+(x-1)^2
f(-x)=f(x),g(-x)=-g(x)
2f(x)+0=(x+1)^2+(x-1)^2=2x^2+2
f(x)=x^2+1
g(x)=(x+1)^2-(x^2+1)=2x
f(x)+g(x)=(x+1)^2
f(-x)+g(-x)=[(-x)+1]^2=(x-1)^2
[f(x)+g(x)]+[f(-x)+g(-x)]=(x+1)^2+(x-1)^2
f(-x)=f(x),g(-x)=-g(x)
2f(x)+0=(x+1)^2+(x-1)^2=2x^2+2
f(x)=x^2+1
g(x)=(x+1)^2-(x^2+1)=2x