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Ник555555551
Ник555555551
04.09.2021 00:17 •  Геометрия

7. Упростите выражение: (sina + cosa)? + (sina - cosa)²​

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Ответ:
Fltkbyf2017
Fltkbyf2017
18.07.2022 01:31

параллелепипеде верны следующие равенства:

\begin{gathered}\vec{AB}=\vec{A_1B_1}=\vec{DC}=\vec{D_1C_1}\\\vec{BC}=\vec{B_1C_1}=\vec{AD}=\vec{A_1D_1}\\\vec{AA_1}=\vec{BB_1}=\vec{DD_1}=\vec{CC_1}\\\end{gathered}AB=A1B1=DC=D1C1BC=B1C1=AD=A1D1AA1=BB1=DD1=CC1

следовательно

\begin{gathered}\vec{AB}+\vec{B_1C_1}+\vec{DD_1}+\vec{CD}=\vec{AB}+\vec{BC}+\vec{CD}+\vec{DD_1}=\vec{AD_1}vec{BD_1}-\vec{B_1C_1}=\vec{BD_1}-\vec{BC}=\vec{CD_1}\end{gathered}AB+B1C1+DD1+CD=AB+BC+CD+DD1=AD1BD1−B1C1=BD1−BC=CD1

2.\begin{gathered}\vec{BN}=\vec{BD}+\vec{DN}=\vec d +\frac{1}{2}\vec{DS}=\vec d+\frac{1}{2}(\vec{BS}-\vec{BD})=\\=\vec d+\frac{1}{2}\vec{BS}-\frac{1}{2}\vec d=\frac{1}{2}\vec d+\frac{1}{2}(\frac{1}{2}(\vec{BA}+\vec{BC}))=\frac{1}{2}\vec d + \frac{1}{4}\vec a + \frac{1}{4}\vec c\end{gathered}BN=BD+DN=d+21DS=d+21(BS−BD)==d+21BS−21d=21d+21(

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Ответ:
lllllll47900732
lllllll47900732
09.09.2020 07:04

1.danced, opened, took , rained, had , washed, did ,watched ,cleaned ,went, made , was , got ,lived , wrote

2.we didn't go to Moscow last summer.

the children didn't have dinner at 2o'clock yesterday.

they didn't watch film last week/

I didn't get up at 8 o'clock yesterday.

it didn't rain two days ago

Ann didn't live in S.Petersburg last year/

She didn't read an untersting book the day before  yesterday.

I didn't my homework after school yesterday.

3.where  the children play in the garden yesterday?

did Tom write a latter three days ago&

What father cook dinneh yesterday&

Who mother go  to work by bus yesterday?

When we have a bath the day before yesterday?

Why Nick come home in the aafternoon?

What grandmother make tea in the morning?

4.1 We didn't have lunch at 1o'clock yesterday.Did we have lunch at 1o'clock yesterday? where we have lunch at 1 o'clock  yesterday? Who have lunch at 1 o'clock yesterday?

4.2 It didn't show last week.Did it show last week? Where it show last week? Who ishow last week?

5/1 I halped the mom yesterday.

5/2 where you live last month?

5/3 Did they wake up at 7 am ?

5/4 We didn't go to school yesterday

5/5Who watch the TV on Sunday ?

 

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