Å‚% = " · "
x x
F (t - ) F (t + )
c c
1 "2F
Å‚%xF - = 0,
c2 "t2
"2
Å‚%x := F1(Ét - kx) F1(Ét + kx)
"x2
É := kc É k
"
1 r
G(x, y, z, t) = F (t " ) r := x2 + y2 + z2
r c
"2G "2G "2G 1 "2G
+ + = .
"x2 "y2 "z2 c2 "t2
"
r := x2 + y2
F = F (x, y, z, t)
1 "2F
Å‚%F = .
c2 "t2
F (x, y, z, t)
× ×
A(x, y, z, t) " × A = 0
×
1 "2A
×
(" · ")A = .
c2 "t2
×
A(x, y, z, t)
U(x, y, z, t) Õ(x, y, z, t)
Ä…Õ+²U Ä…, ²