I encountered Mollweide's formula and I search the net for the proof.. I got this link http://planetmath.org/encyclopedia/ProofOfMollweidesEquations.html . I studied the proof and it requires a lot of trigonometric identities. Can we have another means in proving this identity? A better approach? thanks a lot in advance..:)
By the way the Mollweide's formula is:
Given any triangle with $a,\ b,\ c, \ \alpha ,\ \beta, \ \gamma $.$\frac{a+b}{c}= \frac{\cos (\frac{\alpha - \beta}{2})}{\sin (\frac{\gamma}{2})}$ and $\frac{a-b}{c}= \frac{\sin (\frac{\alpha - \beta}{2})}{\cos(\frac{\gamma}{2})}$