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QUESTION: Hello, my name is Leo and I am studying for my ACTs and have come across a very hard problem that I'm having trouble solving. I am hoping you could go through it and show step-by-step how you got your answer.

I am asked to verify this identity:

((cos a - cos b) / (sin a + sin b)) + ((sin a - sin b) / (cos a + cos b))

ANSWER: That isn't an identity—it is not an equation. Is it typed correctly?

---------- FOLLOW-UP ----------

QUESTION: My apologies, I did make a mistake in typing it; that is all supposed to be set to "= 0"

To make things a bit more clear, I drew up an image of the problem:
http://prntscr.com/2ixaj4

Thanks for taking the time to get back to me, this should help and make things easier for you. Leo

Answer
Leo,
Thanks for clearing that up.
The solution is to give the fractions a common denominator, then apply the Pythagorean Identities
  sin˛α + cos˛α = 1
  sin˛β + cos˛β = 1

http://www.flickr.com/photos/dwread/11928560344/

Janet

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Janet Yang

Expertise

I can answer questions in Algebra, Basic Math, Calculus, Differential Equations, Geometry, Number Theory, and Word Problems. I would not feel comfortable answering questions in Probability and Statistics or Topology because I have not studied these in depth.

Experience

I tutor students (fifth through twelfth grades) and am a Top Contributor on Yahoo!Answers with over 24,000 math solutions.

Publications
Co-author of An Outline of Scientific Writing: For Researchers With English as a Foreign Language

Education/Credentials
I have a Bachelor's degree in Applied Mathematics from the University of California at Berkeley.

Past/Present Clients
George White Elementary School. Homework Help program at the Ridgewood Public Library, Ridgewood, NJ. Individual students.

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