→ iyenn: m(_ _)m 快看!是神 12/11 19:56
→ ntust661: = = 12/11 19:57
→ ntust661:可以問您矩陣的問題嗎 12/11 19:57
推 youmehim:1樓算線代就像在算1+1一樣 12/11 20:00
y'' + y = secx
yh = c1 cosx + c2 sinx
yp = ψ1 cosx + ψ2 sinx
W = 1
ψ1 = -∫ secx sinx dx
= - ∫ tanx dx
= ln cos x
ψ2 = ∫ secx cosx dx
= ∫ dx
= x
yp = ln │cosx│ cosx + x sin x
Y = yh + yp
= c1 cosx + c2sinx + ln │cosx│ cosx + x sin x
根本沒有那種詭異的積分吼= =
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