Ask Singapore Homework?
Upload a photo of a Singapore homework and someone will email you the solution for free.
Question
secondary 3 | A Maths
One Answer Below
Anyone can contribute an answer, even non-tutors.
Pls help to solve q17a
9⋅sin(x) = 2⋅sec(x) = 2 / cos(x)
【square at both sides】
81⋅sin²(x) • cos²(x) = 4
sin²(x) ⋅ ( 1-sin²(x) ) = ⁴⁄₈₁
sin²(x) = a
a - a² = ⁴⁄₈₁
a² - a + ⁴⁄₈₁ = 0
1- 4×1×⁴⁄₈₁ = ⁶⁵⁄₈₁
a = (1 ± √ (⁶⁵⁄₈₁) / 2
a₁ = 0.94790320823 = sin²(x) = (±0.97360320882)²
a₂ = 0.05209679176 = sin²(x) = (±0.22824721632)²
x₁ = 76.8061°
x₂ = 256.8061°
x₃ = 13.1939°
x₄ = 193.1939°
Do you have the answer key together with the working?
See 1 Answer