Sarthaks Test
0 votes
34 views
in Tamilnadu Board by (15 points)
recategorized by

Find extreme value of cosx + cosy + cos(x+y)

Please log in or register to answer this question.

2 Answers

+2 votes
by (187 points)

Also, we know that cos function attains its max value 1 at 0 radians.

so,  x = y = 0

  • x+y = 0

Hence, the maximum value of cos x + cos y + cos (x+y) = 1 + (1)+1=3

Thus, the maximum value of cos x + cos y + cos (x+y) = 3

0 votes
by (30.7k points)

We know that the cos function attains its minimum value as -1 at π radians.

  • So, x = y = π
  • x + y = 2π Now, we can write as;
  • cos(x + y) = cos 2π = 1
  • This is the min value of cos(x + y).

Thus, the minimum value of cos x + cos y + cos (x + y) = -1 + (-1 ) +1 = -1

Also, we know that cos function attains its max value 1 at 0 radians.

so,  x = y = 0

  • x+y = 0

Hence, the maximum value of cos x + cos y + cos (x + y) = 1 + (1 )+1 = 3

Thus, the maximum value of cos x + cos y + cos (x + y) = 3 and minimum value = -1

Related questions

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

Categories

...