1. Chapter 6 Class 12 Application of Derivatives
  2. Serial order wise
  3. Ex 6.2
Check sibling questions

Ex 6.2,14 - Chapter 6 Class 12 Application of Derivatives

Last updated at Dec. 16, 2024 by Teachoo

Transcript

Ex 6.2, 14 Find the least value of a such that the function f given by 𝑓 (π‘₯) = π‘₯2 + π‘Žπ‘₯ + 1 is strictly increasing on (1, 2).We have f(π‘₯) = π‘₯2 + aπ‘₯ + 1 And, f’(π‘₯) = 2π‘₯ + a Given f is strictly increasing on (1 ,2) ∴ f’(π‘₯) > 0 on (1 ,2) Putting value of f’(x) 2π‘₯ + a > 0 on (1 ,2) Let’s put x = 1 and x = 2 and find value of a So, a > βˆ’2 satisfies both equations Thus, we can say that When a > –2 , f(π‘₯) = π‘₯2 + aπ‘₯ + 1 is strictly increasing on (1 , 2) Hence, least value of a is –2 Putting 𝒙 = 1 2(1) + a > 0 2 + a > 0 a > –2 Putting 𝒙 = 2 2(2) + a > 0 4 + a > 0 a > –4
  1. Chapter 6 Class 12 Application of Derivatives
  2. Serial order wise

    3. Ex 6.2

    Ex 6.3 →
Ex 6.3 →
Chapter 6 Class 12 Application of Derivatives
Serial order wise

About the Author

Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science and Computer Science at Teachoo