(-∞, cot 2)∪(cot 5, ∞)
(-∞, cot 5)∪(cot 4, cot 2)
(cot 5, cot 4)
(cot 2, ∞)
Let cot x = t
Then t² - 7t + 10 > 0
On factorizing, (t - 2)(t - 5) > 0
cot x = 2, 5
x = cot⁻¹2, cot⁻¹5
On plotting the x on wavy curve we get
x lie in (-∞, cot 2)∪(cot 5, ∞)