Determinante 3x3
a11 a22 a33 + a12 a23 a31 + a13 a21 a32 - a13 a22 a31 - a12 a21 a33 - a11 a23 a32.



Ecuación plano por tres puntos

(x-x(A_1)) (y(A_1)-y(B_1)) (y(C_2)-y(A_2)) + (y+y(A_1)) (y(B_2)-y(A_2)) (x(C_1)-x(A_1)) + (z-y(A_2)) (x(B_1)-x(A_1)) (y(A_1)-y(C_1)) - (z-y(A_2)) (y(A_1)-y(B_1)) (x(C_1)-x(A_1)) - (y+y(A_1)) (x(B_1)-x(A_1)) (y(C_2)-y(A_2)) - (x-x(A_1)) (y(B_2)-y(A_2)) (y(A_1)-y(C_1)) = 0

---------------- 
 
z=0
 
(x-x(A_1)) (y(A_1)-y(B_1)) (y(C_2)-y(A_2))+ (-y(A_2)) (x(B_1)-x(A_1)) (y(A_1)-y(C_1)) - (-y(A_2)) (y(A_1)-y(B_1)) (x(C_1)-x(A_1)) - (x-x(A_1)) (y(B_2)-y(A_2)) (y(A_1)-y(C_1)) = (y+y(A_1)) ((x(B_1)-x(A_1)) (y(C_2)-y(A_2))  - (y(B_2)-y(A_2)) (x(C_1)-x(A_1))) 


(((x-x(A_1)) (y(A_1)-y(B_1)) (y(C_2)-y(A_2))+ (-y(A_2)) (x(B_1)-x(A_1)) (y(A_1)-y(C_1)) - (-y(A_2)) (y(A_1)-y(B_1)) (x(C_1)-x(A_1)) - (x-x(A_1)) (y(B_2)-y(A_2)) (y(A_1)-y(C_1)))/ ((x(B_1)-x(A_1)) (y(C_2)-y(A_2))  - (y(B_2)-y(A_2)) (x(C_1)-x(A_1)))) -y(A_1) = y

f'_1(x)= (((x-x(A_1)) (y(A_1)-y(B_1)) (y(C_2)-y(A_2))+ (-y(A_2)) (x(B_1)-x(A_1)) (y(A_1)-y(C_1)) - (-y(A_2)) (y(A_1)-y(B_1)) (x(C_1)-x(A_1)) - (x-x(A_1)) (y(B_2)-y(A_2)) (y(A_1)-y(C_1)))/ ((x(B_1)-x(A_1)) (y(C_2)-y(A_2))  - (y(B_2)-y(A_2)) (x(C_1)-x(A_1)))) -y(A_1)

Cambiando los signos a y.

f_1(x)= (((x-x(A_1)) (-y(A_1)+y(B_1)) (-y(C_2)+y(A_2))+ (y(A_2)) (x(B_1)-x(A_1)) (-y(A_1)+y(C_1)) - (y(A_2)) (-y(A_1)+y(B_1)) (x(C_1)-x(A_1)) - (x-x(A_1)) (-y(B_2)+y(A_2)) (-y(A_1)+y(C_1)))/ ((x(B_1)-x(A_1)) (-y(C_2)+y(A_2))  - (-y(B_2)+y(A_2)) (x(C_1)-x(A_1)))) +y(A_1)

Con condicional para la "verntana"

f_1(x)=Si[0 ≤ x ≤ 1.5floor(sqrt((97x(O) - x(O)² - 277) / 28) / 2)², (((x-x(A_1)) (-y(A_1)+y(B_1)) (-y(C_2)+y(A_2))+ (y(A_2)) (x(B_1)-x(A_1)) (-y(A_1)+y(C_1)) - (y(A_2)) (-y(A_1)+y(B_1)) (x(C_1)-x(A_1)) - (x-x(A_1)) (-y(B_2)+y(A_2)) (-y(A_1)+y(C_1)))/ ((x(B_1)-x(A_1)) (-y(C_2)+y(A_2)) - (-y(B_2)+y(A_2)) (x(C_1)-x(A_1)))) +y(A_1)]

-------------------

y=0

(x-x(A_1)) (y(A_1)-y(B_1)) (y(C_2)-y(A_2)) + (y(A_1)) (y(B_2)-y(A_2)) (x(C_1)-x(A_1)) + (z-y(A_2)) (x(B_1)-x(A_1)) (y(A_1)-y(C_1)) - (z-y(A_2)) (y(A_1)-y(B_1)) (x(C_1)-x(A_1)) - (y(A_1)) (x(B_1)-x(A_1)) (y(C_2)-y(A_2)) - (x-x(A_1)) (y(B_2)-y(A_2)) (y(A_1)-y(C_1)) = 0

(((x-x(A_1)) (y(A_1)-y(B_1)) (y(C_2)-y(A_2)) + (y(A_1)) (y(B_2)-y(A_2)) (x(C_1)-x(A_1)) - (y(A_1)) (x(B_1)-x(A_1)) (y(C_2)-y(A_2)) - (x-x(A_1)) (y(B_2)-y(A_2)) (y(A_1)-y(C_1))) / ((y(A_1)-y(B_1)) (x(C_1)-x(A_1)) - (x(B_1)-x(A_1)) (y(A_1)-y(C_1)))) + y(A_2) = z

cambiando z por y

y=(((x-x(A_1)) (y(A_1)-y(B_1)) (y(C_2)-y(A_2)) + (y(A_1)) (y(B_2)-y(A_2)) (x(C_1)-x(A_1)) - (y(A_1)) (x(B_1)-x(A_1)) (y(C_2)-y(A_2)) - (x-x(A_1)) (y(B_2)-y(A_2)) (y(A_1)-y(C_1))) / ((y(A_1)-y(B_1)) (x(C_1)-x(A_1)) - (x(B_1)-x(A_1)) (y(A_1)-y(C_1)))) + y(A_2)

f_2(x)=(((x-x(A_1)) (y(A_1)-y(B_1)) (y(C_2)-y(A_2)) + (y(A_1)) (y(B_2)-y(A_2)) (x(C_1)-x(A_1)) - (y(A_1)) (x(B_1)-x(A_1)) (y(C_2)-y(A_2)) - (x-x(A_1)) (y(B_2)-y(A_2)) (y(A_1)-y(C_1))) / ((y(A_1)-y(B_1)) (x(C_1)-x(A_1)) - (x(B_1)-x(A_1)) (y(A_1)-y(C_1)))) + y(A_2)

Con condicional para la "verntana"

f_2(x)=Si[0 ≤ x ≤ 1.5floor(sqrt((97x(O) - x(O)² - 277) / 28) / 2)², (((x-x(A_1)) (y(A_1)-y(B_1)) (y(C_2)-y(A_2)) + (y(A_1)) (y(B_2)-y(A_2)) (x(C_1)-x(A_1)) - (y(A_1)) (x(B_1)-x(A_1)) (y(C_2)-y(A_2)) - (x-x(A_1)) (y(B_2)-y(A_2)) (y(A_1)-y(C_1))) / ((y(A_1)-y(B_1)) (x(C_1)-x(A_1)) - (x(B_1)-x(A_1)) (y(A_1)-y(C_1)))) + y(A_2)]