Let be a continous function such that for all
Define
for
is a constant function
Use leibniz rule for differentiation under integral sign
using leibniz rule for differentiation under integral sign we get
[ Because f(3x)=f(x)]
Since the derivative of is
for all
, Hence
is a constant function
Let be a continous function such that for all
Define
for
is a constant function
Use leibniz rule for differentiation under integral sign
using leibniz rule for differentiation under integral sign we get
[ Because f(3x)=f(x)]
Since the derivative of is
for all
, Hence
is a constant function