If the equation x2 - kx + 1 = 0 has no real roots then
Given the equation x2 - kx + 1 = 0 has no real roots
a = 1 b = - k c = 1
Thus D = b2 - 4ac < 0
( - k)2 - 4.1.1 < 0
k2 - 4 < 0
k2 < 4
- 2 < k < 2