!"#$%&"'()$"*
!"#"$%&'%()'%("$%&"
*!"#+,-./
01223&045647428&'9#:9 *;4564742<=2394:9>;/
?@AB@%'&#(C0"&!"#"$%
x y
x y
y�+xy2
= 1
y��+ 2y�+ 2y= 0
a0y+a1y�+a2y��+a3y���+· · ·=b
an b x
y�+xy2
= 1
y2
y�= dy
dx =f(x)
dy=f(x)dx
t= 0
N0 N t
dN
dt =−λN
λ
dN
N =−λdt
lnN =−λt+
t= 0 N =N0 lnN0
N =N0e− λt
yp=
ecxQn(x) c�=a c�=b
xecxQn(x) c=a c=b a�=b
x2 ecxQ
n(x) c=a=b