a 2 + b 2 = c 2 0 1 0 0 0 1 1 0 0 x 2 + y x 2 y x^{2} + y 2 x + y = - 5 x - 2 y = 1 Theorem of Pythagoras /* comment here */
test
x 2 1 2 r 1 \sqrt{2r - 1}