The maximum value of sin x . cos x is

(A) 1/4                     (B) 1/2

(C) √2                      (D) 2 √2

 

This question is similar to Ex 6.5, 9 - Chapter 6 Class 12 - Application of Derivatives

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Question 13 The maximum value of sin x . cos x is (A) 1/4 (B) 1/2 (C) √2 (D) 2 √2 Let f(𝒙)=sin⁑π‘₯βˆ™cos⁑π‘₯ =(2 sin⁑π‘₯ cos⁑π‘₯)/2 =(π’”π’Šπ’ πŸπ’™)/𝟐 Since, βˆ’πŸβ‰€π’”π’Šπ’ πœ½β‰€πŸ Putting πœƒ=2π‘₯ βˆ’1≀sin⁑2π‘₯≀1 Dividing by 2 βˆ’1/2≀(𝑠𝑖𝑛 2π‘₯)/2≀1/2 βˆ’πŸ/πŸβ‰€π’‡(𝒙)β‰€πŸ/𝟐 ∴ Maximum value of 𝑓(π‘₯) is 𝟏/𝟐. So, the correct answer is (B).

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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