Simple, but a bit hard, Trigonometry problem.


I've managed to solve it but only after a _massive_ number of
calculations.
Is there any other simpler solution? There must be!

If:
a = Sin(5°)
b = Sin(49°)
c = Sin(87°)

then prove that: Sin(73°) = (a^2 - b^2 + a c) / ( 4 a (a^2 - b^2 +
a c) - (a-b+c) )

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If the symbol of degree inside the Sin() does not appear in some
browsers then the problem is the follow:

If:
a = Sin(5 degrees)
b = Sin(49 degrees)
c = Sin(87 degrees)

then prove that: Sin(73 degrees) = (a^2 - b^2 + a c) / ( 4 a (a^2 -
b^2 + a c) - (a-b+c) )


Thanks for any help.....

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