NTA Abhyas JEE Main2020MathematicsInverse Trigonometric FunctionsPractice
For x ∈ 0 , π 2 , if c o s - 1 7 2 1 + cos 2 x + s i n 2 x - 48 c o s 2 x sin x = x - cos - 1 k cos x , then the value of k is equal to
Options
- A1
- B5
- C7
- D14
Correct answer
C. 7
Step-by-step solution
y = c o s - 1 7 2 1 + cos ⁡ 2 x + s i n 2   x - 48 c o s 2   x sin ⁡ x = c o s - 1 7 cos ⁡ x cos ⁡ x + 1 - 49 cos 2 x 1 - cos 2 x = c o s - 1 cos ⁡ x - c o s - 1 7 cos ⁡ x = x - c o s - 1 7 cos ⁡ x Hence, the value of k = 7