有誰能幫我計計一條中四的數嗎?

a = 2 - [1/1+b]

( 1 / 1 + b ) = 2 - a

1 + b = 1 / ( 2 - a )

b = 1 / ( 2 - a ) - 1


2007-08-07 21:52:51 補充：
b = 1 / ( 2 - a ) - 1 = 1 / ( 2 - a ) - ( 2 -a ) / ( 2 -a )= ( 1 - 2 + a ) / ( 2 - a )= ( a - 1 ) / ( 2 - a )= ( 1 - a ) / ( a - 2 )

2007-08-07 21:54:08 補充：
1 / ( 2 - a ) - 1 同 ( 1 - a ) / ( a - 2 ) 都係啱ka, 不過表達方式唔同。

若 a = 2 - [1/(1+b)] , 則 b = ?
若 a = 2 - [1/(1+b)] ; [1+b] <> 0
則 a + [1/(1+b)] = 2
1/(1+b) = (2 - a)
(2 - a)(1 + b) = 1
(2 - a) + b(2 - a) = 1
b(2 - a) = 1 - ( 2 - a)
b(2 - a) = a - 1
若 (2 - a) <> 0
b = (a - 1) / (2 - a) or b = (1 - a) / (a - 2)

若 a = 2 - [1/1+b] , 則 b = ?
a = 2 - [1/1+b] ;
a=(2+2b-1)/(1+b)=(2b+1)/(1+b)
a(1+b)=2b+1
a+ab=2b+1
(a-2)b=1-a
b=(1-a)/(a-2)

a = 2 - [1/1+b]

[1/1+b] = 2-a

1+b = [1/2-a]

b=[1/2-a] -1