\(100+97+94+...+4+1\)

Số các số hạng trong dãy số trên là:

\(\left(100-1\right):3+1=34\left(số\right)\)

Tổng các số trên bằng:

\(\left(100+1\right)\cdot34:2=1717\)

Tớ đổi chiều lại nhé : `1+4+...+94+97+100`

Khoảng cách : `3`

Số số hạng là :

\(\dfrac{100-1}{3}+1=34\) ( số hạng )

Tổng dãy là :

\(\dfrac{\left(100+1\right)\cdot34}{2}=1717\)

đề bài là ''thực hiện phép tính, tính hợp lí nếu có thể'' bạn ah, chứ mình chép đúng đề bài ak

Local environment: The local environment plays a crucial role in our daily lives. How can we contribute to preserving and protecting our local environment for a sustainable future? City life: City life offers endless opportunities and conveniences, but it also comes with challenges. How can we strike a balance between the fast-paced city life and maintaining our well-being? Teen stress and pressure: Teenagers often face immense stress and pressure in various aspects of their lives. What can be done to support and alleviate the stress and pressure that teenagers experience? Life in the past: Reflecting on life in the past can provide valuable insights and lessons. What are some aspects of life in the past that we can learn from and apply to our present lives? Wonders of Vietnam: Vietnam is known for its breathtaking natural landscapes and rich cultural heritage. What are some of the wonders of Vietnam that you would recommend exploring? Vietnam: Then and now: Vietnam has undergone significant changes over the years. How has Vietnam transformed from the past to the present, and what are some of the notable differences and similarities?

*Tham khảo:

Local environment: The local environment plays a crucial role in our daily lives, providing us with clean air, water, and natural resources. How can we protect and preserve our local environment for future generations?

City life: City life is fast-paced and dynamic, offering a wide range of opportunities and experiences. What are some advantages and disadvantages of living in a city?

Teen stress and pressure: Teenagers often face stress and pressure from school, peers, and family. How can we support and help teenagers cope with the challenges of adolescence?

Life in the past: Reflecting on life in the past can provide valuable insights into our history and culture. What are some lessons we can learn from the experiences of previous generations?

Wonders of Vietnam: Vietnam is home to breathtaking natural landscapes, rich cultural heritage, and delicious cuisine. What are some must-see wonders of Viet Nam for tourists and travelers?

Viet Nam then and now: Viet Nam has undergone significant changes in recent decades, from a war-torn country to a thriving economy. How has Vietnam transformed over the years, and what are some key developments in its history?

Lỗi hình ảnh rồi bạn nhé!

4:

a: góc OBA+góc OCA=180 độ

=>OBAC nội tiếp

b: Xét (O) có

AB,AC là tiếp tuyến

=>AB=AC

mà OB=OC

nên OA là trung trực của BC

=>OA vuông góc BC tại H

=>AB^2=AH*AO