Question

Subiectul I, va rog!

Answer 1

6) Aplicăm teorema cosinusului:

$\it cos A = \dfrac{b^2+c^2-a^2}{2bc}=\dfrac{6^2+5^2-7^2}{2\cdot6\cdot5} = \dfrac{12}{12\cdot5} =\dfrac{1}{5}$