Let f1(x)=x,0≤x≤11, x>10, otherwise
f2(x)=f1(−x) for all x
f3(x)=−f2(x) for all x
f4(x)=f3(−x) for all x
which of the following is necessarily true?
f4(x)=f1(x) for all x
f1(x)=−f3(−x) for all x
f2(−x)=f4(x) for all x
f1(x)+f3(x)=0 for all x
f2(x)=f1(-x) f3(x)=-f2(x) f3(x)=-f1(-x) replace x by -x f3(-x)=-f1(x) ⇒f1(x)=-f3(-x)