Question

Prove the law of sines using the cross product. Here is what I have done so far...

A
B
C
A+B+C=0
Reply Using Drawing


From there I am stuck

Answer 1

Well, C x (A + B) = C x -C = 0
Thus
C x A = - C x B
C x A = B x C

...you take it from here

Answer 2

From there you can express it as

\[ACsin \theta = BCsin \phi \] C cancels and you are left with
\[sin \theta /b = sin \phi /a\]

Phi being the angle between B and C and theta being the angle between A and C.
Yes?

Answer 3

yes

Answer 4

Thank you!