JEE Main & Advanced
Mathematics
Functions
Question Bank
Numerical Value Type Questions - Function
question_answer
If \[f:R\to R\] satisfies \[f\left( x+y \right)=f\left( x \right)+f\left( y \right),\] for all \[x,\,\,y\,\,\in \,\,R\] and \[f\left( 1 \right)=7,\]\[\sum\limits_{r=1}^{n}{f\left( r \right)}=k\left( n \right)\left( n+1 \right)\] then find k.