1. 2sin 60°-3tg 30°=2[tex] \frac{\sqrt{3}}{2} [/tex]-3[tex] \frac{1}{\sqrt{3}} [/tex] =[tex] \frac{2\sqrt{3}}{2} -\frac{3}{\sqrt{3}}=\sqrt{3}-\frac{3}{\sqrt{3}} =\frac{3}{\sqrt{3}}-\frac{3}{\sqrt{3}} =0 [/tex]
2.cos B=AB/BC⇒3/5=AB/BC⇒BC=5AB/3
tg C=AB/AC din relatia AC²=BC²-AB²⇒AC²=(5AB/3)²-AB²⇒AC²=25AB²/9-AB²⇒ AC²=(25AB²-9AB²)/9=16AB²/9⇒AC=4AB/3
tg C=[tex] \frac{AB}{\frac{4AB}{3}}=\frac{3AB}{4AB} [/tex]⇒tg C=3/4
