ABC is a triangle with sides a,b and c. show that :

if then A=2B

I try to use the cosine law, but no result

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- December 15th 2010, 08:41 AMrazemsoft21Show that ....
ABC is a triangle with sides a,b and c. show that :

if then A=2B

I try to use the cosine law, but no result - December 15th 2010, 07:37 PMtonio
- December 16th 2010, 06:09 AMSoroban
Hello, razemsoft21!

Quote:

We are given: .

Law of Cosines:

.[1]

. . . . . .

. . . . . .

. . . . . . .[2]

Since [1] = [2], we have: .

. . Therefore: .

- December 16th 2010, 06:27 AMrazemsoft21
- December 16th 2010, 07:12 AMtonio
- December 18th 2010, 05:36 PMArchie Meade
- December 19th 2010, 03:51 PMrazemsoft21