★【新教學影片】提要045:強制振動問題之數學模式的解 (Proof of ʃ sec x dx = ln|tan x + sec x|+ C)

★【新教學影片】提要045:強制振動問題之數學模式的解 (Proof of ʃ sec x dx = ln|tan x + sec x|+ C)