Question

determinati functiile de gradul intai care verifica relatia( f*f)(x)=4x+2

Answer 1

f(x)=ax+b
f*f=f(f(x)=af(x)+b=4x+2
a(ax+b)+b=4x+2
a²x+ab+b=4x+2 =>
{a²=4  =>  a1= -2 ,  a2=2
{ab+b=2  =>-2b+b=2=>b1=-2
f(x)=-2x-2
a=2=>2b+b=2=>b=2/3
f(x)=2x+2/3