2017 · Q66
If 7 sin²x + 3 cos²x = 4, 0 < x < 90°, then what is the value of tan x ?
Elementary MathematicsTrigonometry
- A√(2)
- B1
- C(√(3))/2
- D1/(√(3))
Explanation
7sin²x + 3(1 − sin²x) = 4 gives 4sin²x = 1, so sinx = 1/2 with 0 < x < 90°, i.e. x = 30°. Then tanx = 1/√3: option D.