1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

A problem in Trigonometry (Properties of Triangles)

Tags:
  1. May 11, 2017 #1
    • Member warned that the homework template must be used, and an effort shown
    In any triangle ABC, prove that $$(b+c-a) \left( \cot {\frac {B}{2}} + \cot {\frac {C}{2}} \right)=2a \cot {\frac {A}{2}} $$
     
  2. jcsd
  3. May 11, 2017 #2
    Did you try to solve this ?
    Also you should not vandalise the template.
     
  4. May 11, 2017 #3
    I tried in several ways, trying to change a, b, c to 2R sin A and like that, or trying the formulae for cot A/2, but got nowhere.
     
  5. May 11, 2017 #4
    Use sine rule and A + B + C = 180.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: A problem in Trigonometry (Properties of Triangles)
Loading...