Apparently, this user prefers to keep an air of mystery about them.
36 System of 4 tedious nonlinear equations: $ (a+k)(b+k)(c+k)(d+k) = $ constant for $1 \le k \le 4$ feb 9 '15
4 System of equations with 2 parameters feb 1 '15
4 Unusual result to the addition jul 1
4 $a^2+b^2=2Rc$,where $R$ is the circumradius of the triangle.Then prove that $ABC$ is a right triangle aug 18