98桃小34題

[oxoxooa]

設x、y為有理數，且f(x+y)=f(x)+f(y)，若f(1)=2，則f(10)=？

感謝鋼琴老師

[thepiano]

f(2) = f(1) + f(1) = 4
f(4) = f(2) + f(2) = 8
f(8) = f(4) + f(4) = 16
f(10) = f(2) + f(8) = 20