Part circle(radius is "r" ) is made from a string.string's lenght is "L".so the part
circle's circumference is also "L".If part circle's area is "A",Find the angle of the part
circle when Area is maximum
,here what I did but never got the answer.what is wrong in this?
setting to zero for the maximum value
now what? answer has to be r(L-2r)/2(as books says).