Răspunsuri

2014-06-17T00:47:28+03:00
T. cosinusului
BC²=AB²+AC²-2×AB×AC×cosA
cosA=(AB²+AC²-BC²)/2×AB×AC
cos A=(2+1+2√3+3-4)/2√2(1+√3)
cos A=1/√2=√2/2⇒A=45