已知f(x)=3的x次方,求证:(1)f(x)乘以f(x)=f(x+y) (2)f(x)除以f(y)=f(x-y)
热心网友
(1) 因为f(x)*f(y)=(3^x)*(3^y)=3^(x+y) f(x+y)=3^(x+y) 所以f(x)*f(y)=f(x+y)(2) 同理,只需代入即可.f(x)/f(y)=3^(x-y) f(x-y)=3^(x-y) 所以f(x)/f(y)=f(x-y)
热心网友
(1)f(x)=3^x故f(x)*f(y)=3^x * 3^y=3^(x+y)=f(x+y)(a^x * a^y =a ^(x+y) )(2)f(x)/f(y)=3^x/3^y=3^(x-y)=f(x-y)(a^x * a^y =a^(x-y) )