Use app×
Ask a Question
QUIZARD
QUIZARD
JEE MAIN 2026 Crash Course
NEET 2026 Crash Course
CLASS 12 FOUNDATION COURSE
CLASS 10 FOUNDATION COURSE
CLASS 9 FOUNDATION COURSE
CLASS 8 FOUNDATION COURSE

Prove that: `cos175^(@)+cos65^(@)+cos55^(@)=0`

← Prev Question Next Question →
0 votes
215 views
in Mathematics by (64.1k points)
closed by
Prove that:
`cos175^(@)+cos65^(@)+cos55^(@)=0`
Challenge Your Friends with Exciting Quiz Games – Click to Play Now!

1 Answer

0 votes
by (61.1k points)
selected by
 
Best answer
LHS `=cos175^(@)+cos65^(@)+cos55^(@)`
`=2cos120^(@)cos55^(@)+cos55^(@)`
`=2cos(180^(@)-60^(@))cos55^(@)+cos55^(@)`
`=-2cos60^(@)+cos55^(@)`
`=-2(1/2)cos55^(@)+cos55^(@)`
`-cos55^(@)+cos55^(@)=0`
=RHS Hence Proved.
← Prev Question Next Question →

Find MCQs & Mock Test

  1. JEE Main 2026 Test Series
  2. NEET Test Series
  3. Class 12 Chapterwise MCQ Test
  4. Class 11 Chapterwise Practice Test
  5. Class 10 Chapterwise MCQ Test
  6. Class 9 Chapterwise MCQ Test
  7. Class 8 Chapterwise MCQ Test
  8. Class 7 Chapterwise MCQ Test

Related questions

0 votes
1 answer
`cos175^(@)+cos65^(@)+cos55^(@)=?`
asked May 7, 2020 in Mathematics by DivyanshuKumar (64.1k points)

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

User Contribution to Sarthaks eConnect
Managed by Sarthaks Digitizing India
...