Originally Posted by
lehder Hi,
F is the group of numerical functions.
First "F" you write . Apparently you mean the group of all real functions.
$\displaystyle E={ f_{(a;b)}\in F \ \ /\forall x \in \mathbb{R}/ \ \ f_{(a;b)}(x)=(ax+b)e^{2x} }$
Now you write "E" without curly parentheses $\displaystyle \{,\}$, but you apparently meant $\displaystyle E:=\{f_{(a,b)}\in F\;;\;\forall\,x\in\mathbb{R}\,,\,\,f_{(a,b)}(x):= (ax+b)e^{2x}\}$
I must show that (H,+) is a subgroup, how to do it please??