★【新教學影片】提要(☆002☆):引用降階法求通解#01▕ Solve x(x – 1)y'' – xy' + y = 0.

★【新教學影片】提要(☆002☆):引用降階法求通解#01▕ Solve x(x – 1)y'' – xy' + y = 0.