v v t t t
u v u e
t t
d d d
t t t t t t t
d
dt
t
x t x t u v
u t t t t t t
M x x dx N x x dx
M x x x x N x x x x
F h x
x x x h x x h x x x
x
A B CB AC
A B C B
A C
z r si
Tr si i
ir s i r s
z r si
r si r si
a b
a d bc a d ad bc
c d
i
i b
i a b
a i b
a b i
T
iT T