ABC =triunghi dreptunghic, cu <B=60°, <C=30°
cos B=AB/BC
sitim ca : cosB =cos 60°=1/2
⇒1/2=4/BC
⇒BC= 8
sin B=AC/BC
stim ca : sin B=sin 60°=√3/2
⇒√3/2=AC/8
⇒AC=8√3/2=4√3
tg B=AC/AB
stim ca: tg B=tg 60°=√3
√3=4√3/4
ctgB=AB/AC
stim ca: ctg B=ctg 60°=√3/3
√3/3=4/4√3=1/√3=√3/3