Question

Succes cine stie si poate sa rezolve in ordine

Answer 1

Am atasat rezolvarea.

Answer 2

Testul 3 (de sus)

1) sin²55° + sin²35° = sin²55° + cos²(90°-35°) = sin²55° + cos²55° = 1

2)  Nu există un astfel de triunghi.

3) Aplicăm teorema sinusurilor:

$\it \dfrac{AB}{sinC}=2R \Rightarrow AB=2RsinC =2\cdot9\cdot sin30^o =2\cdot9\cdot\dfrac{1}{2} =9$

4)

[tex]\it x\in \left(\pi,\dfrac{3\pi}{4}\right) \Rightarrow sinx\ \textless \ 0 \\\;\\ \\\;\\ sinx=-\sqrt{1-cos^2x} =- \sqrt{1-\dfrac{3}{4}} =-\sqrt{\dfrac{1}{4}}=-\dfrac{1}{2}[/tex]

5)

[tex]\it S = \dfrac{AB\cdot BC\cdot sinB}{2} \Rightarrow BC = \dfrac{2S}{AB\cdot sinB} =\dfrac{2\cdot3}{5sin45^o}=\dfrac{2\cdot3}{5\cdot\dfrac{\sqrt2}{2}} = \\\;\\ \\\;\\ =\dfrac{2\cdot3\cdot2}{5\sqrt2}= \dfrac{ \not2\cdot3\cdot2\sqrt2}{5\cdot \not2} = \dfrac{6\sqrt2}{5}[/tex]