Check sibling questions

Find the intervals in which the function f given by f (x) = x2 – 4x + 6 is strictly increasing:
(a) (-∞, 2) ∪ (2,∞)   (b) (2,∞)
(c) (-∞, 2)                (d) (-∞, 2] ∪ (2,∞)  

This question is inspired from - Example 10 - Chapter 6 Class 12 Application of Derivatives


Transcript

Question 5 Find the intervals in which the function f given by f (x) = x2 – 4x + 6 is strictly increasing: (a) (−∞, 2) ∪ (2,∞) (b) (2,∞) (c) (−∞, 2) (d) (−∞, 2] ∪ (2,∞) f(𝑥) = 𝑥2 – 4𝑥 + 6 Calculate f’(𝒙) 𝑓’ (𝑥) = 2𝑥 – 4 Calculate f’(𝒙) = 0 2𝑥 – 4 = 0 2𝑥 = 4 𝑥 = 4/2=2 Hence 𝑥 = 2 divide real line into 2 disjoint intervals. Plotting points on number line Hence. f is strictly increasing in interval (2 , ∞) So, the correct answer is (b)

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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