★【新教學影片】提要(☆002☆):引用降階法求通解#02▕ Solve (x + 1)y'' – (x + 2)y' + y = eˣ (x + 1)².

★【新教學影片】提要(☆002☆):引用降階法求通解#02▕ Solve (x + 1)y'' – (x + 2)y' + y = eˣ (x + 1)².