NTA Abhyas JEE Main2020MathematicsTrigonometric EquationsPractice
If s i n 2 x + 10 - x 2 = 9 - x 2 + 2 s i n 2 x + c o s 2 x , then x lies in
Options
- A- 8,8
- B- 3,3
- C- 17 , 17
- D- 21 , 21
Correct answer
B. - 3,3
Step-by-step solution
s i n 2 x + 10 - x 2 = 9 - x 2 + s i n 2 x + s i n 2 x + c o s 2 x ⇒ s i n 2 x + 1 + 9 - x 2 = 9 - x 2 + s i n 2 x + 1 x + y + z = x + y + z , if x ,   y ,   z have the same sign ⇒ s i n 2 x 9 - x 2 ≥ 0 ⇒ 9 - x 2 ≥ 0 ⇒ x ∈ - 3,3