v(a)=k(a-a)a^2 correct
v(a)=k(0)a^2
v(a)= 0 , zero times anything else is zero
v(r)= k(a-r)r^2 where k is a constant
evaluate v at a.
This is what I got when I solved but it is not correct.
v(a)=k(a-a)a^2
v(a)=ka^2
2 answers
oh i see