intai de toate trebuie sa transormam cos in sin. Cum facem asta? ne folosim de [tex] cos^{2} x+ sin^{2} x=1 =\ \textgreater \ sin ^{2} x=1-cos ^{2} x =\ \textgreater \ sinx= \sqrt{1- cos^{2}x } [/tex] inlocuim. [tex]sinx= \sqrt{1- \frac{1}{4} } = \sqrt{ \frac{4-1}{4} } = \sqrt{ \frac{3}{4} } = \frac{ \sqrt{3} }{2} [/tex] .Folosim teorema sinusurilor [tex] \frac{a}{sinA} = \frac{b}{sinB} = \frac{c}{sinC} =2R[/tex] inlocuim [tex] \frac{3}{ \frac{1}{2} }=2R =\ \textgreater \ 3=2R =\ \textgreater \ R=3[/tex]
