Duljine stranica trokuta su
![a](/media/m/6/d/2/6d2832265560bb67cf117009608524f6.png)
,
![b](/media/m/e/e/c/eec0d7323095a1f2101fc1a74d069df6.png)
i
![c](/media/m/e/a/3/ea344283b6fa26e4a02989dd1fb52a51.png)
, a veličine kutova nasuprot stranica duljina
![b](/media/m/e/e/c/eec0d7323095a1f2101fc1a74d069df6.png)
i
![c](/media/m/e/a/3/ea344283b6fa26e4a02989dd1fb52a51.png)
su
![\beta =50^\circ](/media/m/d/d/4/dd478d36a5d950c40446266396b912c5.png)
i
![\gamma=100^\circ](/media/m/f/6/5/f656fb0f935ce0827e3b87553caa8081.png)
. Dokaži jednakost
%V0
Duljine stranica trokuta su $a$, $b$ i $c$, a veličine kutova nasuprot stranica duljina $b$ i $c$ su $\beta =50^\circ $ i $\gamma=100^\circ $. Dokaži jednakost $$
ab=c^2-b^2.
$$