ртпооаоаьмо вгаьвоьаьсsinx + cos x + sin2x = 1
sin x + cos x + 2sinx cosx -1=0
sin x + cos x +2sinx cosx -(sin²x+cos²x)=0
(sin x + cos x) + 2sinx cos x - (sin²x+cos²x+2sinx cosx -2sinx cos x)=0
(sin x+ cos x)+2sinx cosx - (sin x + cos x)² +2sinx cosx=0
(sin x + cos x)² + (sinx + cosx)+4sinxcosx=0
Пусть sin x + cos x = t причем (-√2 ≤ t ≤ √2), тогда возведем оба части до квадрата, имеем
(sin x + cos x)² = t²
1+2sinx cosx = t²
2sinxcosx = t²-1
Заменяем
t²+t+2*(t²-1)=0
t²+t+2t²-2=0
3t²+t-2=0
D=1+24 = 25
t1=(-1+5)/6=2/3
t2=(-1-5)/6 = -1
Возвращаем к замене
\begin{gathered}\sin x+\cos =-1\\ \sqrt{2} \sin(x+ \frac{\pi}{4} )=-1 \\ \sin(x+ \frac{\pi}{4} )=- \frac{1}{ \sqrt{2} } \\ x+ \frac{\pi}{4}=(-1)^{n+1} \frac{\pi}{4}+ \pi n,n \in Z\\ x=(-1)^{n+1} \frac{\pi}{4}- \frac{\pi}{4}+ \pi n,n \in Z\end{gathered}
sinx+cos=−1
2
sin(x+
4
π
)=−1
sin(x+
4
π
)=−
2
1
x+
4
π
=(−1)
n+1
4
π
+πn,n∈Z
x=(−1)
n+1
4
π
−
4
π
+πn,n∈Z
\begin{gathered}\sin x+\cos x= \frac{2}{3} \\ \sqrt{2} \sin(x+ \frac{\pi}{4})= \frac{2}{3} \\ \sin (x+ \frac{\pi}{4})= \frac{ \sqrt{2} }{3} \\ x=(-1)^n\arcsin( \frac{ \sqrt{2} }{3} )- \frac{\pi}{4}+ \pi n,n \in Z\end{gathered}
sinx+cosx=
3
2
2
sin(x+
4
π
)=
3
2
sin(x+
4
π
)=
3
2
x=(−1)
n
arcsin(
3
2
)−
4
π
+πn,n∈Z
Объяснение:
1
1 We haven't been reading books for a year.
2You haven't been runing very much lately.
3Jane hasn't been teaching English all year.
4Mark hasn't been doing exercise regularly
5Martin hasn't been eating regularly
2
1Every Monday Sally drives her kids to football practice.
2work/study
3starts
4don't swim/is
5agree
6talks
3
1 is Andrea swiming in the lake
2 is Martin washing his T-shirt?
3 are the guys carring the buckets?
4 is Peter holding the string of the kite?
4
1 is barking
2 are washing
3 are learning
5
1 don't play
6
1Where Joe does live? 2 Why don't they visit us? 3 When do we board the plane?
не знаю насколько правильно
The early years.
Pushkin's father came of an old boyar family; his mother was a granddaughter of Abram Hannibal, who, according to family tradition, was an Abyssinian princeling bought as a slave at Constantinople (Istanbul) and adopted by Peter the Great, whose comrade in arms he became. Pushkin immortalized him in an unfinished historical novel, Arap Petra Velikogo (1827; The Negro of Peter the Great). Like many aristocratic families in early 19th-century Russia, Pushkin's parents adopted French culture, and he and his brother and sister learned to talk and to read in French. They were left much to the care of their maternal grandmother, who told Aleksandr, especially, stories of his ancestors in Russian. From Arina Rodionovna Yakovleva, his old nurse, a freed serf (immortalized as Tatyana's nurse in Yevgeny Onegin), he heard Russian folktales. During summers at his grandmother's estate near Moscow he talked to the peasants and spent hours alone, living in the dream world of a precocious, imaginative child. He read widely in his father's library and gained stimulus from the literary guests who came to the house.
Вот биография Пушкина