Q:

1) Find function domain f(x) = sqrt( 2sin x - 1 )

Accepted Solution

A:
Answer:{x ∈ ℝ : x β‰₯ Ο€/6 +2Ο€n and x ≀ Ο€/6 + 2Ο€n and n ∈ β„€} Step-by-step explanation:sinx can run from -1 to +1 2sinx can run from -2 to +2 2sinx -1 can run from -3 to +1 However, the square root is imaginary when x < 0. So, the condition is 2sinx -1 β‰₯ 0 2sinx β‰₯ 1 sinx β‰₯ Β½ x β‰₯ Ο€/6 (30Β°) So, in the interval [0, 2Ο€], Ο€/6 ≀ x ≀ 5Ο€/6 However, the sine is a cyclic function and repeats itself every 2Ο€. Over all real numbers, the condition is (Ο€/6 +2Ο€n) ≀ x ≀ (5Ο€/6 + 2Ο€n). The domain is then {x ∈ ℝ : x β‰₯ Ο€/6 +2Ο€n and x ≀ Ο€/6 + 2Ο€n and n ∈ β„€}