NTA Abhyas JEE Main2020MathematicsApplication of DerivativesPractice
The points on the curve f x = x 1 - x 2 , where the tangent to it has slope equal to unity, are x 1 , y 1 , x 2 , y 2 and x 3 , y 3 . Then, x 1 + x 2 + x 3 is equal to
Options
- A0
- B3 2
- C3 4
- D3
Correct answer
A. 0
Step-by-step solution
f ′ x = 1 − x 2 1 − x − 2 x 1 − x 2 2 ⇒ 1 + x 2 = 1 + x 4 - 2 x 2 ⇒ x 4 - 3 x 2 = 0 ⇒ x = 0 , ± 3 ⇒ x 1 + x 2 + x 3 = 0