2 / 2\ \13 - d /
(13 - d^2)^2 при d = 4
(13 - d^2)^2
(13 - (4)^2)^2
(13 - 4^2)^2
9
(13.0 - d^2)^2
2 / 2\ \-13 + d /
4 2 169 + d - 26*d