NTA Abhyas 2020
- Exam
- NTA Abhyas
- Year
- 2020
- Subject
- Mathematics
- Chapter
- Indefinite Integration
NTA Abhyas 2020 · Mathematics · Indefinite Integration
If the integral I = ∫ 2x^ 2 4 + x^ 2 dx = 2x - f(x) + c , where f...
If the integral , where then the minimum value of is (where,
Options
- A
- B
- C
- D
Correct answer
B.
Step-by-step solution
I = 2∫ \left(\dfrac{x^{2} + 4 - 4}{x^{2} + 4}\right)dx= 2∫ \left(1 - \dfrac{4}{x^{2} + 4}\right)dx= 2\left(x - \dfrac{4}{2}\tan^{- 1} \left(\dfrac{x}{2}\right)\right) + c= 2x - 4\tan^{- 1} \left(\dfrac{x}{2}\right) +
∴ f\left( x\right) = 4\tan^{- 1} \left(\dfrac{x}{2}\right)
So, min \left( f\left(x\right)\right) = 4\tan^{- 1} \left(-1\right) = - \pi
∴ f\left( x\right) = 4\tan^{- 1} \left(\dfrac{x}{2}\right)
So, min \left( f\left(x\right)\right) = 4\tan^{- 1} \left(-1\right) = - \pi