mình làm bài 3 rồi ý nên mình chỉ cần làm bài 4 thôi <3
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Những câu hỏi liên quan
QL
21 tháng 8 2021
O1=O2( vì 2 góc đối đỉnh)
O3 và O4 thì làm theo cách hai góc kề bù
Vd :O1+O3=180 độ (2 góc kề bù)
Suy ra :120 độ +O3=180 độ
Vậy từ đó tính ra đc O3 ,tương tự O4 cũng vậy
H
0
giúp mình làm phần test 4 với ạ, chỉ cần ghi đáp án thôi ạ. Đáp án cũ chưa chắc đúng nên cần gợi ý ạ
17 tháng 11 2021
I like English the most and I will share with everyone how to study English effectively without getting bored.
1. If we often watch TV every day, we should watch movies in English or read some books or stories to improve our listening and reading skills.
2. Buy an English pack to learn with pronunciation and writing so we can pronounce English correctly and rarely make spelling mistakes
3. Join the dance or singing activities in English at school or at home so that you can both show your own talents and reduce boredom while learning English.
Here are my sharing on the most effective way to learn English without getting bored. I ask the teachers to choose my lesson
17 tháng 11 2021
English is a popular and important language today. If you have English as a second mother tongue, then great, all success will come to you. But what about the opposite, everything is deadlocked if you are a fresh graduate who needs a job to think logically with English. Here is Hai 's full English experience:
-Learn English vocabulary.(Every day 10 words is enough to break naxo^-^)
-Learn sentence patterns, English structures. (Don't be discouraged)
-Learn to speak English (Sweet Western accent needs to be shown at this time.)
-Learn to chase, imitate native speakers.
-Listen to English music.
-Read English newspapers (Actually, I'm too lazy)
-If you really need an English degree, you should sign up for a reputable course. The real thing to do is you have to be interested in it, passionate about it.
(I'm a person who loves my mother tongue, so I won't use hello much).
Everyone, please refer.
K
13 tháng 12 2020
11 c)
\(a^2+2\ge2\sqrt{a^2+1}\Leftrightarrow a^2+1-2\sqrt{a^2+1}+1\ge0\Leftrightarrow\left(\sqrt{a^2+1}-1\right)^2\ge0\) (luôn đúng)
K
13 tháng 12 2020
12 a) Có a+b+c=1\(\Rightarrow\) (1-a)(1-b)(1-c)= (b+c)(a+c)(a+b) (*)
áp dụng BĐT cô-si: \(\left(b+c\right)\left(a+c\right)\left(a+b\right)\ge2\sqrt{bc}2\sqrt{ac}2\sqrt{ab}=8\sqrt{\left(abc\right)2}=8abc\) ( luôn đúng với mọi a,b,c ko âm )
b) áp dụng BĐT cô-si: \(c\left(a+b\right)\le\dfrac{\left(a+b+c\right)^2}{4}=\dfrac{1}{4}\)
Tương tự: \(a\left(b+c\right)\le\dfrac{1}{4};b\left(c+a\right)\le\dfrac{1}{4}\)
\(\Rightarrow abc\left(a+b\right)\left(b+c\right)\left(c+a\right)\le\dfrac{1}{4}\dfrac{1}{4}\dfrac{1}{4}=\dfrac{1}{64}\)
22 tháng 4 2016
Mình làm topic 2 nha:
My most favorite season is fall and I love everything about it. Usually it starts at the end of May in our country and lasts till the middle of July.
The weather is best during fall and you won't feel the heat of summer or the cold wind of winter. The nature arranges itself with the beautiful green and flowers are noticed all around the places.
I like the scenic beauty, charming weather, festivities and freshness of this season. This is a distinctive season and is known as the queen of seasons in our country. The newly grown green leaves of trees, the colorful flowers, the chirping of the birds and crisp and mild air of fall are some of the noticeable changes in our country. After the hot summer ends, the falls comes and people in our country love this season.
Fall is season that marks the transition from summer into winter and the night falls later than winter. The farmers start harvesting seeds in this season and they become quite active during this season.
I usually get vacation at the beginning of the fall and visit my hometown. This is a perfect vacation for me as my hometown becomes even more beautiful. Because of geographical location and culture, we have 2-3 major festival during this time and people enjoys the festivals and weathers.
D
23 tháng 4 2016
As a student, I don’t have much free time beside those I love, so my summer vacation is the duration during which I often busy myself with many things at home all day. In the day time,
I often do sundry things for my grandmother and help my parents to do housework. In the evening, I go out with some of my old friends.
We often chat with each other in a cafe. Usually, when I am free from doing housework, I go and visit close relatives in my neighborhood and ask them about their life and business. In the late evening, I watch films on TV or read novels or books to widen my understanding. I often
go to bed very late.
In my mind, I always want my short summer vacations to be not only comfortable for me but also useful for my beloved people.
Chúc bạn học tốt
NB
1
16 tháng 8 2021
bài 7
A=\(\dfrac{x+2}{\sqrt{x^3}-1}+\dfrac{\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}{\left(x+\sqrt{x}+1\right)}+\dfrac{-x-\sqrt{x}-1}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}\)
A=\(\dfrac{x+2+x-1-x-\sqrt{x}-1}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}\)
A=\(\dfrac{x-\sqrt{x}}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}\)=\(\dfrac{\sqrt{x}\left(\sqrt{x}-1\right)}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+x+1\right)}\)
A=\(\dfrac{\sqrt{x}}{x+\sqrt{x}+1}\)
bài 8
P=\(\left[\dfrac{\sqrt{x}+2}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}-\dfrac{\sqrt{x}-2}{\left(\sqrt{x}-1\right)^2}\right].\dfrac{\left(x-1\right)^2}{4x}\)
P=\(\dfrac{\left(\sqrt{x}+2\right)\left(\sqrt{x}-1\right)-\left(\sqrt{x}-2\right)\left(\sqrt{x}+1\right)}{\left(\sqrt{x}-1\right)^2\left(\sqrt{x}+1\right)}.\dfrac{\left(x-1\right)^2}{4x}\)
P=\(\dfrac{2\sqrt{x}}{\left(x-1\right)\left(\sqrt{x}-1\right)}.\dfrac{\left(x-1\right)^2}{4x}\)=\(\dfrac{x-1}{2\sqrt{x}\left(\sqrt{x}-1\right)}\)
P=\(\dfrac{\sqrt{x}+1}{2\sqrt{x}}\)
bài 9
P=\(\left[\dfrac{2\sqrt{xy}}{\left(\sqrt{x}-\sqrt{y}\right)\left(\sqrt{x}+\sqrt{y}\right)}-\dfrac{\sqrt{x}+\sqrt{y}}{2\left(\sqrt{x}-\sqrt{y}\right)}\right].\dfrac{2\sqrt{x}}{\sqrt{x}-\sqrt{y}}\)
P=\(\dfrac{4\sqrt{xy}-\left(\sqrt{x}+\sqrt{y}\right)^2}{2\left(\sqrt{x}-\sqrt{y}\right)\left(\sqrt{x}+\sqrt{y}\right)}.\dfrac{2\sqrt{x}}{\sqrt{x}-\sqrt{y}}\)
P=\(\dfrac{2\sqrt{xy}-x-y}{\left(\sqrt{x}-\sqrt{y}\right)\left(\sqrt{x}+\sqrt{y}\right)}.\dfrac{\sqrt{x}}{\sqrt{x}-\sqrt{y}}\)
P=\(\dfrac{-\left(\sqrt{x}-\sqrt{y}\right)^2}{\left(\sqrt{x}-\sqrt{y}\right)\left(\sqrt{x}+\sqrt{y}\right)}.\dfrac{\sqrt{x}}{\sqrt{x}-\sqrt{y}}\)
P=\(\dfrac{-\sqrt{x}}{\sqrt{x}+\sqrt{y}}\)
bài 10
P=\(\left[\dfrac{1}{\sqrt{x}+2}-\dfrac{2}{\left(\sqrt{x}+2\right)^2}\right]:\left[\dfrac{2}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)}-\dfrac{1}{\sqrt{x}-2}\right]\)
P=\(\dfrac{\sqrt{x}+2-2}{\left(\sqrt{x}+2\right)^2}:\dfrac{2-\sqrt{x}-2}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)}\)
P=\(\dfrac{\sqrt{x}}{\left(\sqrt{x}+2\right)^2}.\dfrac{\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)}{-\sqrt{x}}\)=\(\dfrac{-\left(\sqrt{x}-2\right)}{\sqrt{x}+2}\)
11 tháng 7 2016
1-2-3+4+5-6-7+8+...+97-98-99+100
= (1 - 2 - 3 + 4) + (5 - 6 - 7 + 8) + ... + (97 - 98 - 99 + 100)
=0 + 0 + 0 +......+0
=0 . 50
=0
11 tháng 7 2016
1 - 2 - 3 + 4 + 5 - 6 - 7 + 8 + ... + 97 - 98 - 99 + 100 ( có 100 số; 100 chia hết cho 4)
= (1 - 2 - 3 + 4) + (5 - 6 - 7 + 8) + ... + (97 - 98 - 99 + 100)
= 0 + 0 + ... + 0
= 0
Ủng hộ mk nha ☆_★^_-
Bài 4.
a) MSC: 9
\(\dfrac{1}{3}=\dfrac{1\times3}{3\times3}=\dfrac{3}{9};\dfrac{7}{9}=\dfrac{7}{9}\)
b) MSC: 24
\(\dfrac{3}{4}=\dfrac{3\times6}{4\times6}=\dfrac{18}{24};\dfrac{4}{24}=\dfrac{4}{24}\)
c) MSC: 30
\(\dfrac{7}{10}=\dfrac{7\times3}{10\times3}=\dfrac{21}{30};\dfrac{19}{30}=\dfrac{19}{30}\)
d) MSC: \(20\)
\(\dfrac{1}{4}=\dfrac{1\times5}{4\times5}=\dfrac{5}{20};\)
\(\dfrac{2}{5}=\dfrac{2\times4}{5\times4}=\dfrac{8}{20}\)
Bài 4:
a; \(\dfrac{1}{3}\) = \(\dfrac{1\times3}{3\times3}\) = \(\dfrac{3}{9}\); \(\dfrac{7}{9}\)
Vậy hai phân số \(\dfrac{1}{3}\) và \(\dfrac{7}{9}\) đã được quy đồng mẫu số thành
\(\dfrac{3}{9};\dfrac{7}{9}\)
b; \(\dfrac{3}{4};\dfrac{4}{24}\)
\(\dfrac{4}{24}=\dfrac{1}{6}\) = \(\dfrac{1\times2}{6\times2}\) = \(\dfrac{2}{12}\)
\(\dfrac{3}{4}=\dfrac{3\times3}{4\times3}\) = \(\dfrac{9}{12}\)
Vậy các phân số: \(\dfrac{3}{4};\dfrac{4}{24}\) đã được quy đồng mẫu số thành các phân số sau: \(\dfrac{9}{12}\); \(\dfrac{2}{12}\)
c; \(\dfrac{7}{10}\) = \(\dfrac{7\times3}{10\times3}\) = \(\dfrac{21}{30}\); \(\dfrac{19}{30}\)
Vậy các phân số \(\dfrac{7}{10};\dfrac{19}{30}\) đã được quy đồng mẫu số các phân số thành \(\dfrac{21}{30};\dfrac{19}{30}\)
d; \(\dfrac{1}{4};\dfrac{1}{5}\)
\(\dfrac{1}{4}=\dfrac{1\times5}{4\times5}\) = \(\dfrac{5}{20}\)
\(\dfrac{1}{5}\) = \(\dfrac{1\times4}{5\times4}\) = \(\dfrac{4}{20}\)
Vậy hai phân số: \(\dfrac{1}{4};\dfrac{1}{5}\) đã được quy đồng mẫu số thành các phân số:
\(\dfrac{5}{20};\dfrac{4}{20}\)