已知x+ 1 x- 1
已知x+ 1 x- 1
----- =根号8.求 -------
x x
x加上1/x等于根号下8,求x减去1/x
----- =根号8.求 -------
x x
x加上1/x等于根号下8,求x减去1/x
数学人气:878 ℃时间:2020-02-05 04:25:35
优质解答
(x + 1/x)^2 = x^2 + 2 + 1/(x^2) = 8
故:x^2 + 1/(x^2) = 6
故:(x - 1/x)^2 = x^2 - 2 + 1/(x^2) = 4
所以:x - 1/x = ±2
经验证都符合题意.
我来回答
类似推荐