Question

待定系数法8+2D-2E+F=0.36+5D+3E+F=0.10+3D-E+F=0应该怎么解出DEF.怎么消元的.

Answer 1

{8+2D-2E+F=0 ①

{36+5D+3E+F=0 ②

{0+3D-E+F=0 ③

③-①得 -8+D+E=0 ④

②-①得 26+3D+5E=0 ⑤

解④、⑤得D=33、E=-25

把D=33、E=-25代入③得F=-124

所以方程组的解是

{D=33,

{E=-25

{F=-124