triangles on the sphere

[Guest]

I am having problems getting this question started, any help is appreciated.

Let Triangle ABC be a right triangle on the unit spere S and with right angle at C. Proove that:

sin(|Tri ABC|) = [sin(a)*sin(b)]/[1+ cos(a)*cos(b)]

where sin(|Tri ABC|) means sin(area of triangle ABC)

What is the analogous result in euclidian geometry?

thanks in advance

 

[happy]

Don't double post!

http://www.mathgoodies.com/forums/topic ... C_ID=27239

 

[Guest]

Don't double post!

http://www.mathgoodies.com/forums/topic ... C_ID=27239

Sorry about that, I did not know that was not allowed

 

[Gene]

I personally have no problem with double posting as long as it is on a different forum. Post it there then post it here for the correct answer :evil:

 

[stapel]

I don't think it's so much a matter of the multi-forum posting being "wrong", as much as the fact that so many of the same people volunteer at these various forums ("fora"?). Tutors either get aggravated by spending twenty minutes writing up a reply, only to find the exact same question posted three other places, or else the tutors figure "Oh, never mind; it's posted three other places, so somebody else will answer it". Either way, the multi-posting may quickly result in a greatly reduced frequency of replies.

Just FYI....

Eliz.