Ryuto did start dating Runa, but Ryuto's pals warn him that it's "a joke for those popular types." Ryuto feels the cold stares of his classmates and worries he could get dumped at any moment as he starts planning his first date with his new girlfriend.
Listen up. 
Memorize the addition formulas like this:
:أنصت. احفظ صيغ الجمع هكذا
Gesetz des Additionstheorems
Escuchen,
pueden memorizar las fórmulas así:
Escuchad,
podéis memorizar las fórmulas así:
Vous devez absolument retenir
ces formules trigonométriques.
Regole delle formule di addizione
Prestem atenção. Memorizem as
fórmulas de adição deste jeito:
Это надо выучить. Такие формулы 
легче запомнить следующим образом: