✔ 最佳答案
圖片參考：
http://sphotos-h.ak.fbcdn.net/hphotos-ak-prn1/v/524996_492581910808735_965143120_n.jpg?oh=a742598b14414554d4379611650a185b&oe=5129392B&__gda__=1361707098_95f360b0a1ef7ae8e4bc602eeea2f94a
11a)
f(1) = (1 - a)(1 - b)(1 + 1) - 3
1 = 2(a - 1)(b - 1) - 3
(a - 1)(b - 1) = 2
b)
a < b
a - 1 < b - 1 ,
故 a - 1 = 1 , b - 1 = 2
得 a = 2 , b = 3。
c)
f(x) - g(x)
= ( (x - 2)(x - 3)(x + 1) - 3 ) - (x³ - 6x² - 2x + 7)
= (x² - 5x + 6)(x + 1) - 3 - (x³ - 6x² - 2x + 7)
= x³ - 5x² + 6x + x² - 5x + 6 - 3 - (x³ - 6x² - 2x + 7)
= x³ - 4x² + x + 3 - (x³ - 6x² - 2x + 7)
= 2x² + 3x - 4
f(x) = g(x)
f(x) - g(x) = 0
2x² + 3x - 4 = 0
x = [ - 3 ± √(9 - 4(2)(-4)) ] / [2(2)]
x = (- 3 ± √41) / ****************************************************
9ˣ⁺² = 36
9ˣ = 36/9²
3²ˣ = 4/9
3ˣ = 2/3 或 -2/3(捨去因 3ˣ > 0)
(A)
2013-02-22 21:20:59 補充：
x = (- 3 ± √41) / ****************************************************
should be
x = (- 3 ± √41) / 4
2013-02-22 21:23:20 補充：
x = (- 3 ± √41) / ****************************************************
應是
x = (- 3 ± √41) / 4
