Question

Ma ajutati la ex. 1 si 3?
multumesc mult^^

Answer 1

1. 2sin 60°-3tg 30°=2$\frac{\sqrt{3}}{2}$-3$\frac{1}{\sqrt{3}}$ =$\frac{2\sqrt{3}}{2} -\frac{3}{\sqrt{3}}=\sqrt{3}-\frac{3}{\sqrt{3}} =\frac{3}{\sqrt{3}}-\frac{3}{\sqrt{3}} =0$

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=$\frac{AB}{\frac{4AB}{3}}=\frac{3AB}{4AB}$⇒tg C=3/4