// marta: oblicz; a)2sin60'*cos20'−2ctg45' b)sin²45' + cos60' −−−−−−−−−−−−−−−−−−−−−− = sin30' * cos 30' c)(tg60' − sin45') −−−−−−−−− −−−−−− = (cos60' cos45') d) sin 30' * tg60' + cos 30' −−−−−−−−−−−−−−−−−−−−−−−−−−−−− = ctg60'

chabun: https://matematykaszkolna.pl/strona/421.html