Cho tam giác ABC có trực tâm H. CMR: `tan A.\vec{HA}+tan B.\vec{HB}+tan C.\vec{HC}=\vec{0}`

D(x) = (x − 2)x 2 − 9(x − 2). ai làm cho e câu này ạ e xin cảm ơn

Lập bảng Axit.(gốc axit,axit,tên axit) tên:-Cl,-Br,-L,=S,-HCO3,=CO3,-NO3,-NO2,-HSO4,=SO4,-H2PO4,=HPO4,///PO4,-OH,-AIO2,=Zn02=,SO3

Cho M là 1 điểm bất kỳ ở miền trong tam giác ABC CMR: `S_{MBC}\vec{MA}+S_{MAC}\vec{MB}+S_{MAB}\vec{MC}=\vec{0}`

Giúp với ạ. Cần siêu gắp lắm lun ý. Cảm ơn rất nhiều

Mấy bạn mà kh làm để cho mai mình nộp là mình dận dận dận

Bài đầu tiên điền dấu cậu thích hợp

5. Although Nam is not an intelligent student, he can learn very fast. -> In spite of ___________________________________________________________ 6. Although it was raining heavily, we still went toschool. -> Despite______________________________________________________________ 7. Although he has a physical handicap, he has become a successful businessman. -> Despite______________________________________________________________ 8.Because of the cheap price, my wife insists on buying the Tivi. -> Because ____________________________________________________________ 9. Although he felt tired, he stayed up to keep us company. -> In spite of____________________________________________________________ 10.Because I studied hard, I passed the exam. -> Because of __________________________________________________________ 11. They didn’t play well, but they won the game. -> Although____________________________________________________________ 12. Despite the very bad traffic, we arrived on time. -> Although ___________________________________________________________ 13.Since he was careless, Tom lost the game. -> Because of___________________________________________________________ 14.Because there was an accident, I was late. -> Because of __________________________________________________________ 15.She failed the University entrance exam because her grades were bad. -> Because of ____________

Cho tập hợp A= {0;1;2} , tìm tập hợp con của B Chọn đáp án đúng và giải thích cách giải B=4 B=6 B=8 B=10

Cho tam giác ABC có các đường cao AD, BE, CF. CMR ABC là tam giác đều nếu `\vec{AD}+\vec{BE}+\vec{CF}=\vec{0}`