Question

Stie cineva cum pot reduce la o varianta mai simpla fractia: cos10 grade x cos120 grade x tg 240 grade/ sin10 grade x cos60 grade x ctg170 grade.
Multumesc mult.

Answer 1

Răspuns:

Explicație pas cu pas:

$\dfrac{cos10*cos120*tg240}{sin10*cos60*ctg170} =\dfrac{cos10*cos(180-60)*tg(180+60)}{sin10*cos60*ctg(180-10)} =\\=\dfrac{cos10*(-cos60)*tg60}{sin10*cos60*(-ctg10)} =\dfrac{cos10*tg60}{sin10*ctg10} =\dfrac{cos10*tg60}{cos10}=tg60=\sqrt{3}$

Aplicate formule de reducere la cadranul I și sinα·ctgα=cosα