При каких значениях х значение производной функции равно 0?

f(x)=5*(sinx - cosx) + √2 * cos5x

ПОДРОБНО

I think summer is the best season of all because it is warm, the nature is beautiful and we have great opportunities for rest. Summer is a time of holidays. We can go anywhere, spend our time near a river or a lake on fresh, green grass, swim in warm water, or climb mountains, play different games, ride a bicycle and so on.I spend my summer holidays at my granny’s. There are many things there to do. What I did most of the time - I swam in the sea and sunbathed. Sometimes I made a fire with my friends at the seaside and cooked potatoes there. It was wonderful. We told anecdotes to each other, and did everything we wanted. I also got used to walk alone in the forest.When August was coming to its end, I went on a small voyage by ship. The ship name was “Sevastopol”.But this summer wasn’t for me only sugar and honey. I have passed through the graduating exams after school and entering exams in the university. So the bigger part of my summer vacations I spent sitting with the books. Of course, it was not interesting, but I’m glad that I did it because now I’m a student of the best university in our country.

№1

Примем

А - количество одногривенных

В - количество двугривенных

1 грив=0,1 руб

2 грив=0,2 руб

тогда

0,1*А+0,2*В=27

А+В=170

А=170-Б

0,1*(170-В)+0,2*В=27

17-0,1*В+0,2*В=27

0,1*В=10

В=100 - количество двугривенных

А=170-100=70 - количество одногривенных

2)

 Примем

х - количество учеников Пифагора

тогда

х-х*1/2-х*1/4-х*1/7=3

х*28/28-х*14/28-х*7/28-х*4/28=3*28/28

х*(28-14-7-4)/28=3*28/28

х*3/28=3*28/28

х=(3*28/28)/(3/28)=28 - количество учеников Пифагора

3)

примем

а-количество жетонов в первом мешке

в-количество жетонов во втором мешке

тогда

а+в=250

а-25=в+25

а=в+25+25=в+50

в+50+в=250

2*в=200

в=200/2=100-количество жетонов во втором мешке

тогда

а=100+50=150-количество жетонов в первом мешке