Определенный интеграл и среднее значение
Mercedes Euklid 21 - one of the most advanced calulators from early 30's is introduced in a short but comprehensive video.
The rest of the Youtube chanel.
Warning. Did you try the problem by yourself first? Blind rewriting problem to computer and puting down the answer may have serious negative influence on your education. The optimal way how to use this application is to solve the problem and then check your result against computer generated answer.