Question

已知x=（根号2）-1/（根号2）+1，y=（根号2）+1/（根号2）-1，求(x^2-y^2)/(x^2-y^2)的值.

哦不好意思题目打错了 是(x^2-y^2)/(x^2+y^2).

Answer 1

你好！

x = (√2 -1)² / (√2+1))(√2-1) = (√2 -1)² = 3 - 2√2
y = (√2+1)² / (√2-1)(√2+1) = 3+2√2
x+y = 6
x-y = - 4√2
xy = 1

x² - y² = (x+y)(x-y) = 6×(-4√2) = - 24√2
x²+y² = (x+y)² - 2xy = 6² - 2 = 34

原式 = - 24√2 /34 = - 12√2 /17

Answer 2

先把x,y化简得x=3-2倍根号2
y=3+2倍根号2
带入

Answer 3

或者是你打错了，打错了请追问

追问

恩是打错了 是(x^2-y^2)/(x^2+y^2).

Answer 4

这答案不是1么…求的东西错了吧