Oblicz: a)cos8/7π*cos1/7π+sin8/7π*sin1/7π b)sinπ/18*sin4/9π-cosπ/18*cos4/9π Konrad: Oblicz: a)cos8/7π*cos1/7π+sin8/7π*sin1/7π b)sinπ/18*sin4/9π−cosπ/18*cos4/9π