Question

Tìm kiếm x y z x-1/y =1 y-1/z =1 z-1/x =1

Answer 1

y - 1/z = 1   ==>   y = 1 + 1/z

z - 1/x = 1   ==>   z = 1 + 1/x

==>   y = 1 + 1/(1 + 1/x) = 1 + x/(x + 1) = (2x + 1)/(x + 1)

x - 1/y = x - (x + 1)/(2x + 1) = (2x ² - 1)/(2x + 1) = 1

==>   2x ² - 1 = 2x + 1

==>   2x ² - 2x - 2 = 0

==>   x ² - x - 1 = 0

==>   x = (1 ± √5)/2

If you start solving for z, then for x, then for y, you would get the same equation as above (with y in place of x), and the same thing happens if you solve for x, then y, then z. So it turns out that x = y = z.