The reason why it cannot be negative is that the origin of the problem was to determine the length of all sides of a likesided triangle thus can't be negative.
I still think that using the quadratic equation is the simplest way of solving it.
solved it now
a2 + a2 = a2 + 2a + 1
simplified it to a quadraticequation
0 = -a2 + 2a + 1
a1 = 1 + sq.root of 2
a2 = 1 - sq.root of 2
a2 is negative therefore a1 is the right answer
which gives a = 2,41
just looking for a quick solution for my equation, seems like my head is just working the wrong way coz I know it's not a hard one:
a2 + a2 = (a + 1)2
a = ?