Question

死命讀

求講解 完全不會寫

2fm²
05-2
.H. 設x=2+5,若x+]=(x+
=(x+-)}-k(x+-),則k值為」
X
X
(9+b)_3ab (a+b))
973ab(a+b)+B

Answer 1

Ny-Ålesund

奇怪的題目

(a + b)^3 = a^3 + 3a^2b + 3ab^2 + b^3 = a^3 + b^3 + 3ab(a + b)

=> a^3 + b^3 = (a + b)^3 - 3ab(a + b)

a = x, b = 1/x

ab = 1 => k = 3

那這樣題目給 x = ... 的意義是?