For

tw

o di

men

sion

al:

, the

equ

atio

n (2

0) is

as

belo

w

Met

ric:

Chr

isto

ffel

s sy

mb

ols:

Th

e eq

uati

on (

20)

can

be

calc

ulat

ed a

s

in w

hich

,

The

refo

re,

Pot

enti

al f

unc

tion

:

For

cas

e I:

th

e eq

uat

ion

of

anh

arm

onic

sys

tem

in a

per

iodi

c fi

eld

Let

:

The

refo

re,

For

cas

e II

: th

e n

onli

nea

r eq

uat

ion

of a

par

amet

rica

lly

exci

ted

dam

ped

pen

dul

um

Thu

s,

=0

=0

For

cas

e II

I: t

he

equa

tion

of

anha

rmon

ic s

yste

m in

a p

erio

dic

fiel

d

,