JEE Exam > JEE Questions > sin 51° + cos 81° =?a)-sin132°...
Start Learning for Free
sin 51° + cos 81° =?
- a)-sin132°
- b)sin132°
- c)-cos21°
- d)cos21°
Correct answer is option 'D'. Can you explain this answer?
| FREE This question is part of | Download PDF Attempt this Test |
Verified Answer
sin 51° + cos 81° =?a)-sin132°b)sin132°c)-cos21...
Two angles are said to be complementaryif their su
m is equals 90 degrees.a ) sin ( 90 - A ) = cos Ab ) cos ( 90 - A ) = sin AAc
Most Upvoted Answer
sin 51° + cos 81° =?a)-sin132°b)sin132°c)-cos21...
Sin 51 + cos 81 = cos 21L.H.S. = sin 51 + cos 81= sin 51 + sin 9[coz cos(90 - x) = sin x]= 2 sin 30 cos 21{coz sin A + sin B = 2 sin [(A+B)/2] cos [(A-B)/2]}= cos 21 = R.H.S.
HENCE PROVED !!!!!!!, APPROVE IF USEFULL
HENCE PROVED !!!!!!!, APPROVE IF USEFULL
Free Test
FREE
| Start Free Test |
Community Answer
sin 51° + cos 81° =?a)-sin132°b)sin132°c)-cos21...
According to the given problem ,
LHS = sin 51 + cos 81
= sin 51 + cos ( 90 - 9 )
= sin 51 + sin 9
= 2 × sin ( 51 + 9 ) /2 × cos ( 51 - 9 ) /2
[ since trigonometric transformations ,
Sin C + Sin D = 2 Sin ( C + D ) /2 Cos ( C - D ) /2 ]
= 2 sin 60 /2 × cos 42 / 2
= 2 × sin 30 × cos 21
= 2 × (1 / 2) × cos 21 [ since sin 30 = 1 / 2 ]
= cos 21
= RHS
Therefore,
Sin 51 + cos 81 = cos 21
I hope it helps you.
LHS = sin 51 + cos 81
= sin 51 + cos ( 90 - 9 )
= sin 51 + sin 9
= 2 × sin ( 51 + 9 ) /2 × cos ( 51 - 9 ) /2
[ since trigonometric transformations ,
Sin C + Sin D = 2 Sin ( C + D ) /2 Cos ( C - D ) /2 ]
= 2 sin 60 /2 × cos 42 / 2
= 2 × sin 30 × cos 21
= 2 × (1 / 2) × cos 21 [ since sin 30 = 1 / 2 ]
= cos 21
= RHS
Therefore,
Sin 51 + cos 81 = cos 21
I hope it helps you.
Attention JEE Students!
To make sure you are not studying endlessly, EduRev has designed JEE study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in JEE.
|
Explore Courses for JEE exam
|
|
Similar JEE Doubts
Top Courses for JEEView all
sin 51° + cos 81° =?a)-sin132°b)sin132°c)-cos21°d)cos21°Correct answer is option 'D'. Can you explain this answer?
Question Description
sin 51° + cos 81° =?a)-sin132°b)sin132°c)-cos21°d)cos21°Correct answer is option 'D'. Can you explain this answer? for JEE 2024 is part of JEE preparation. The Question and answers have been prepared according to the JEE exam syllabus. Information about sin 51° + cos 81° =?a)-sin132°b)sin132°c)-cos21°d)cos21°Correct answer is option 'D'. Can you explain this answer? covers all topics & solutions for JEE 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for sin 51° + cos 81° =?a)-sin132°b)sin132°c)-cos21°d)cos21°Correct answer is option 'D'. Can you explain this answer?.
sin 51° + cos 81° =?a)-sin132°b)sin132°c)-cos21°d)cos21°Correct answer is option 'D'. Can you explain this answer? for JEE 2024 is part of JEE preparation. The Question and answers have been prepared according to the JEE exam syllabus. Information about sin 51° + cos 81° =?a)-sin132°b)sin132°c)-cos21°d)cos21°Correct answer is option 'D'. Can you explain this answer? covers all topics & solutions for JEE 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for sin 51° + cos 81° =?a)-sin132°b)sin132°c)-cos21°d)cos21°Correct answer is option 'D'. Can you explain this answer?.
Solutions for sin 51° + cos 81° =?a)-sin132°b)sin132°c)-cos21°d)cos21°Correct answer is option 'D'. Can you explain this answer? in English & in Hindi are available as part of our courses for JEE.
Download more important topics, notes, lectures and mock test series for JEE Exam by signing up for free.
Here you can find the meaning of sin 51° + cos 81° =?a)-sin132°b)sin132°c)-cos21°d)cos21°Correct answer is option 'D'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of
sin 51° + cos 81° =?a)-sin132°b)sin132°c)-cos21°d)cos21°Correct answer is option 'D'. Can you explain this answer?, a detailed solution for sin 51° + cos 81° =?a)-sin132°b)sin132°c)-cos21°d)cos21°Correct answer is option 'D'. Can you explain this answer? has been provided alongside types of sin 51° + cos 81° =?a)-sin132°b)sin132°c)-cos21°d)cos21°Correct answer is option 'D'. Can you explain this answer? theory, EduRev gives you an
ample number of questions to practice sin 51° + cos 81° =?a)-sin132°b)sin132°c)-cos21°d)cos21°Correct answer is option 'D'. Can you explain this answer? tests, examples and also practice JEE tests.
|
|
Explore Courses for JEE exam
|
|
Suggested Free Tests
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
|
© EduRev
|
Education Revolution
|
Follow Us
|
Signup to see your scores
go up within 7 days!
Access 1000+ FREE Docs, Videos and Tests
Takes less than 10 seconds to signup