✔ 最佳答案
............. ＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿
...........／................＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿
.........／.............／.............＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿ = 2
........／...........／...........／...........＿＿＿＿＿＿＿＿＿＿＿＿＿＿
＿ .／ a+.....／ a+.....／ a+.....／ a+ ……
... V...........V....... ......V............. ..V
Consider the equation x² = a+x
x = √(a+x)
= √(a+√(a+x)
=√(a+√(a+√(a + ...
SO
............. ＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿
...........／................＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿
.........／.............／.............＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿
........／...........／...........／...........＿＿＿＿＿＿＿＿＿＿＿＿＿＿
＿ .／ a+.....／ a+.....／ a+.....／ a+ ……
... V...........V....... ......V............. ..V
is the solution of x² = a+x
x² - x - a = 0
x = [1+√(1+4a)]/2 = 2
1+√(1+4a) = 4
√(1+4a) = 3
1+4a = 9
4a = 8
a = 2
2006-12-19 20:38:45 補充：
唔信可以用calculator計吓
