Question

Cum se faceau exercitiile de genul:

8 cos 30° - 3√2 cos 45° -√3 tg 60° ctg 60°

Si explicatii

Answer 1

tan - tangenta si cot - cotangenta (Latexu e in engleza si folosesc deja asa)

$\displaystyle Deoarece:~\cos30^\circ=\frac {\sqrt 3}{2}~si~\cos45^\circ=\frac{\sqrt 2}2~si~\tan x \times \cot x=1:\\ \\ 8\times \cos30^\circ-3\sqrt 2\cos45^\circ-\sqrt 3\times \tan60^\circ\times \cot 60^\circ=\\ \\ =8\times \frac{\sqrt 3}2-3\times \sqrt2\times \frac {\sqrt 2}2-\sqrt 3\times 1=\\ \\ =4\times \sqrt 3-3-\sqrt 3=\\ \\ =3\times \sqrt 3-3$

Answer 2

$cos30=\frac{\sqrt{3}}{2} \\ \\ 8\cdot cos30=4\sqrt{3} \\ \\ cos45=\frac{1}{\sqrt{2}} \\ \\ 3\sqrt{2}\cdot cos45=3 \\ \\ tg60=\sqrt{3} \\ \\ ctg60=\frac{1}{\sqrt{3}} \\ \\ \sqrt{3}\cdot tg60\cdot ctg60=\sqrt{3} \\ \\ 4\sqrt{3}-3-\sqrt{3}=3\sqrt{3}-3$