Răspuns:
Tg²30+ctg²60=2/3
Explicație pas cu pas:
Trebuie calculat: Tg²30+ctg²60.
Tg30=sin30/cos30=(1/2)/(rad(3)/2)=rad(3)/3
Ctg60=cos60/sin60=(1/2)/(rad(3)/2)=rad(3)/3.
Asa cum era de asteptat: ctg60=tg30.
Deci expresia devine:
[Rad(3)/3]²+[rad(3)/3]²=2×[rad(3)/3]²=2×3/9=2/3
