JEE Main2013MathematicsDifferentiationActual
If y = sec tan - 1 x , then d y d x at x = 1 is equal to
Options
- A1
- B2
- C1 2
- D1 2
Correct answer
C. 1 2
Step-by-step solution
Given, y = sec tan - 1 x Differentiating both sides w.r.t. x , we get, d y d x = sec tan - 1 x tan tan - 1 x · 1 1 + x 2 At x = 1 , we have, tan - 1 x = π 4 d y d x = sec π 4 × tan π 4 1 + 1 2 = 2 2 = 1 2