− t 2 t 1 3 + t 4 t 1 3 + 2 t 2 t 3 t 1 2 − t 3 t 1 2 + t 2 t 4 t 1 2 − t 2 t 3 t 4 t 1 2 − 2 t 4 t 1 2 + t 1 2 − 2 t 2 t 3 t 1 + t 3 t 1 − t 2 t 4 t 1 + t 2 t 3 t 4 t 1 + 2 t 4 t 1 − t 1 + t 2 t 3 − t 3 t 4 {\displaystyle -t_{2}t_{1}^{3}+t_{4}t_{1}^{3}+2t_{2}t_{3}t_{1}^{2}-t_{3}t_{1}^{2}+t_{2}t_{4}t_{1}^{2}-t_{2}t_{3}t_{4}t_{1}^{2}-2t_{4}t_{1}^{2}+t_{1}^{2}-2t_{2}t_{3}t_{1}+t_{3}t_{1}-t_{2}t_{4}t_{1}+t_{2}t_{3}t_{4}t_{1}+2t_{4}t_{1}-t_{1}+t_{2}t_{3}-t_{3}t_{4}}
