How to prove these two condition??????2. let f be a funetion defined on r which satisfy the condition s+)=s()f/w}vxyer then, if f is continuous at a point c the

how to prove these two condition??????2. Let f be a funetion defined on R which satisfy the condition S+)=S()f/W}VxyeR Then, if f is continuous at a point c then f is continuous at all points ofR 3. Let f:R->R be a function which satisty the property ) F}sH VxeR i) s(r+»)=f(7)+f(v) Vx,yeR Then f(x)= cx VxeR where c=f{1)