Pregunta: 12. Classify each of the following equations and reduce it to canonical form: (a) yuzu - Xuyy = 0, x > 0, y >0; (b) Uzz + (sech*x) Hyy = 0, (c) yềuzz + z’uyy = 0, (d) 4x2 - (sech‘z) Uyy = 0, (e) Uzz + 6uzy + 9uyy + 3y uy = 0, (f) y’Uzz + 2xy Ury + 2x? uyy + xyz = 0, I (g) uzz - (2 cos x) uzy + (1 + cos² x) Uyy +u = 0, (h) uzz + (2 cosec y) uzy + (cosecy) uyy

12. Classify each of the following equations and reduce it to canonical form: (a) yuzu - Xuyy = 0, x > 0, y >0; (b) Uzz + (sech*x) Hyy = 0, (c) yềuzz + z’uyy = 0, (d) 4x2 - (sech‘z) Uyy = 0, (e) Uzz + 6uzy + 9uyy + 3y uy = 0, (f) y’Uzz + 2xy Ury + 2x? uyy + xyz = 0, I (g) uzz - (2 cos x) uzy + (1 + cos² x) Uyy +u = 0, (h) uzz + (2 cosec y) uzy + (cosecy) uyy = 0. (i) uzz - 2 uzy + Uyy +3u; - u+1 = 0, (i) uzz - y uw + un - u + x2 = 0, (k) + uy - T 11, + = 0.