Online Course Discussion Forum

Blue Geometry P20

 
 
Picture of Charles Zhang
Blue Geometry P20
by Charles Zhang - Tuesday, January 5, 2021, 3:21 PM
 
I have found cos(B/2) = ((a+c)^2 - b(b-a))/(2a)(b+c), and I am not sure how to proceed from here.


Any help would be appreciated!

 
Picture of Charles Zhang
Re: Blue Geometry P20
by Charles Zhang - Wednesday, January 6, 2021, 9:37 PM
 

Note: this is for Winter Camp

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Re: Blue Geometry P20
by John Lensmire - Saturday, January 16, 2021, 2:09 PM
 

Thanks for your patience here Charles!

Looks like you're on the right track. Few questions (as hints):

  1. What does Law of Cosines tell us about cos(B)?
  2. Can we turn this into an equation involving cos(B/2) using a trig. identity?

Combining this with your expression from above should give an equation you can solve for cos(B/2).

Picture of Charles Zhang
Re: Blue Geometry P20
by Charles Zhang - Saturday, January 16, 2021, 6:22 PM
 
My work
Picture of Areteem Professor
Re: Blue Geometry P20
by Areteem Professor - Tuesday, January 26, 2021, 9:56 PM
 

Did you see the post in here about this?