For which of the following functions is f(a+b)=f(a)+f(b) for al positive numbers a and b?GHong14 wrote:
a) f(x)=x^2
b) f(x)=x+1
c) f(x)= sqr(x)
d) f(x)=2/x
e) f(x)=-3x
A=> f(a)=a^2, f(b)=b^2, f(a+b)=(a+b)^2 OR a^2+b^2=a^2+ b^2 +2ab False
B=> f(a)=a+1, f(b)=b+1, f(a+b)=a+b+1 OR a+b+1=a+1+b+1 False
C=> f(a)=sqr(a), f(b)=sqr(b), f(a+b)=sqr(a+b) OR sqr(a)+sqr(b)=sqr(a+b) False
D=> f(a)=2/a, f(b)=2/b, f(a+b)=2/(a+b) OR 2/a + 2/b = 2/(a+b) False
E=> f(a)=-3a, f(b)=-3b, f(a+b)=-3(a+b) OR -3a - 3b = -3(a+b) True
