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NV
24 tháng 4 2024

Em kiểm tra lại đề \(BC\) cắt \(\left(AB'C\right)\) tại C nên giữa chúng ko có khoảng cách

Hay là mặt phẳng \(\left(AB'C'\right)\)?

NV
23 tháng 4 2024

a.

\(\left\{{}\begin{matrix}SO\perp\left(ABCD\right)\Rightarrow SO\perp BD\\BD\perp AC\left(\text{hai đường chéo hv}\right)\end{matrix}\right.\)

\(\Rightarrow BD\perp\left(SAC\right)\Rightarrow BD\perp SA\)

Mà \(SA\perp OP\left(gt\right)\)

\(\Rightarrow SA\perp\left(PBD\right)\)

b.

\(AC=\sqrt{AB^2+BC^2}=a\sqrt{2}\Rightarrow OC=\dfrac{1}{2}AC=\dfrac{a\sqrt{2}}{2}\)

\(\Rightarrow SO=\sqrt{SC^2-OC^2}=\dfrac{a\sqrt{14}}{2}\)

\(V=\dfrac{1}{3}SO.AB.AD=\dfrac{a^3\sqrt{14}}{6}\)

c.

Chắc đề ghi nhầm, (SCD) là mặt chứ đâu phải đường

Gọi E là trung điểm CD, tam giác SCD cân tại S \(\Rightarrow SE\perp CD\)

Tam giác OCD cân tại O \(\Rightarrow OE\perp CD\)

\(\Rightarrow CD\perp\left(SOE\right)\)

Mà \(CD=\left(SCD\right)\cap\left(ABCD\right)\)

\(\Rightarrow\widehat{SEO}\)  là góc giữa (SCD) và (ABCD)

\(OE=\dfrac{1}{2}AD=\dfrac{a}{2}\) (đường trung bình)

\(tan\widehat{SEO}=\dfrac{SO}{OE}=\sqrt{14}\Rightarrow\widehat{SEO}\approx75^02'\)

d.

\(\left\{{}\begin{matrix}AO\cap\left(SCD\right)=C\\AC=2OC\end{matrix}\right.\) \(\Rightarrow d\left(A;\left(SCD\right)\right)=2d\left(O;\left(SCD\right)\right)\)

Trong tam giác vuông SEO, từ O kẻ \(OH\perp SE\) (1)

Theo cmt, \(CD\perp\left(SEO\right)\Rightarrow CD\perp OH\) (2)

(1);(2) \(\Rightarrow OH\perp\left(SCD\right)\Rightarrow OH=2\left(O;\left(SCD\right)\right)\)

Hệ thức lượng:

\(OH=\dfrac{SO.OE}{\sqrt{SO^2+OE^2}}=\dfrac{a\sqrt{210}}{30}\)

\(\Rightarrow d\left(A;\left(SCD\right)\right)=2OH=\dfrac{a\sqrt{210}}{15}\)

//Ko hiểu đề cho 2 điểm M và N làm gì, ko liên quan gì đến toàn bộ 4 câu hỏi luôn

NV
23 tháng 4 2024

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Write a paragraph of 100-120 words about "what skills do you think will be helpful for a university student? Why?, using suggested ideas:   - Time management   + Manage workload and complete tasks on time especially   + Create detailed plans to avoid missing any tasks or deadlines   + Prioritize important things related to the study   - Budgeting   + Prioritize essential costs from tuition and books to social activities and personal needs   + Set the foundation for good...
Đọc tiếp

Write a paragraph of 100-120 words about "what skills do you think will be helpful for a university student? Why?, using suggested ideas:

 

- Time management

 

+ Manage workload and complete tasks on time especially

 

+ Create detailed plans to avoid missing any tasks or deadlines

 

+ Prioritize important things related to the study

 

- Budgeting

 

+ Prioritize essential costs from tuition and books to social activities and personal needs

 

+ Set the foundation for good financial habits that will benefit students throughout their lives.

 

+ Set aside money for unexpected expenses, such as medical emergencies or urgent travel, reducing financial stress during challenging times.

 

- Communication skills

 

+ Easily express ideas both verbally and in writing, listen to others and understand instructions and information

Help students have more relationships so that they can learn and work effectively in groups with others

 

-Teamwork skills

 

+ Build positive relationships with others and collaborate effectively when working in groups or

 

teams

 

+ Improve the overall quality of the team's work if being able to work in a team well

0
Write a paragraph of 100-120 words about "What job do you want in the future?   What qualifications, skills and experience do you need to have?, using suggested ideas: * Qualifications: need to have a university dregree in...... at ..university.   - Skills:   Communication skills   + Easily express ideas both verbally and in writing, listen to others and understand instructions and information   + Help students have more relationships so that they can learn and work effectively...
Đọc tiếp

Write a paragraph of 100-120 words about "What job do you want in the future?

 

What qualifications, skills and experience do you need to have?, using suggested ideas: * Qualifications: need to have a university dregree in...... at ..university.

 

- Skills:

 

Communication skills

 

+ Easily express ideas both verbally and in writing, listen to others and understand instructions and information

 

+ Help students have more relationships so that they can learn and work effectively in groups with others

 

-Teamwork skills

 

+ Build positive relationships with others and collaborate effectively when working in groups or

 

teams

 

+ Improve the overall quality of the team's work if being able to work in a team well

 

- Organizational skills

 

+ Organize work to make it easier to access and review through making to-do lists and color-coding

 

notes.

 

+ Have a clear plan of how to approach studying and know how to prioritize tasks and manage time so that all important work is completed and all goals are met.

 

* Experience: have a part-time job in different companies, do some research related to the job, apply for internships at a variety of companies, do volunteer work, and ask for advice from people who have deep knowledge about the job

0