prove cos(81+A)=sin(9-A)

This question was asked in our test
in Trigonometry Answers by

Your answer

Your name to display (optional):
Privacy: Your email address will only be used for sending these notifications.
Anti-spam verification:
To avoid this verification in future, please log in or register.

2 Answers

yu must thank 81 & 9 be DEGREES... kauz 81+9=90 deg.. sine & kosine be 90 deg apart... so kosine(x)=sine(x+90 deg) for all x < infinity & sine(x)=kosine(x-90 deg) for all x
by
cos (81+A)=sin(9-A) so, sin(90-(81+A)=sin(9-A) by property cos(90-@)=sin @ sin(9-A)=sin(9-A) =1
by

Related questions

1 answer
prove 1 + tan x / sin x + cos x = sec x
asked May 7, 2012 in Trigonometry Answers by anonymous | 1.0k views
1 answer
How to prove: (1-cos(x))÷sin(x)=tan(0.5x)
asked Sep 2, 2011 in Trigonometry Answers by anonymous | 2.9k views
Welcome to MathHomeworkAnswers.org, where students, teachers and math enthusiasts can ask and answer any math question. Get help and answers to any math problem including algebra, trigonometry, geometry, calculus, trigonometry, fractions, solving expression, simplifying expressions and more. Get answers to math questions. Help is always 100% free!

Most popular questions within the last 3000 days

  1. 50+50-25X0+2+2= (19)
  2. it takes 10 road workers 5 days to complete a road repair when working 2 hours a day.Working at the same pace,how many days will it take 2 people working 5 hours a day to finish it? (3)
  3. Solve 15 -1(12÷4+1)? (4)
  4. 8:4(5+2) (3)
  5. How can i represent 1/3; 3/3; 7/3; 10/3 and 15/3 on a number line? (1)

Most popular tags

87,516 questions
100,279 answers
2,420 comments
731,562 users