user-avatar
htvt1908
2 năm trước
Giúp mik vs ạ Bài 4. Cho ABC vuông tại A. Vẽ AH – BC tại H, HD perp AB tại D ,HE – AC tại E, đặt ABC = alpha . Chứng minh rằng 1) AD.AB=AE.AC=DE^ 2 . 2) AD.BD+AE.EC=AH^ 2 . 3) 1/(D * H ^ 2) + 1/(H * C ^ 2) = 1/(B * H ^ 2) + 1/(H * E ^ 2) 4) HC=BC sin^ 2 B=BH tan^ 2 B; BH = BC * sin^2 C = HC * tan^2 C
Thích Trả lời Chia sẻ

Các câu hỏi liên quan

GIÚP MIK VỚI Ạ MIK ĐANG CẦN GẤP VIII. Read the passage and answer the questions below David wants to buy a Christmas present for a very special person, his mother. David’s father gives him $5.00 pocket money a week and David puts $2.00 a week into his bank account. After three months David takes $20.00 out of his bank account and goes to the shopping mall. He looks and looks for a perfect gift. Suddenly he sees a beautiful brooch in the shape of his favourite pet. He says to himself, “My mother loves jewelry, and the brooch costs only $17.00.” He buys the brooch and takes it home. He wraps the present in Christmas paper and places it under the tree. He is very excited and he is looking forward to Christmas morning to see the joy on his mother’s face. But when his mother opens the present she screams with fright because she sees a spider. 1. Who does David get his money from? 2. What does David want to buy his Mother? 3. How much money does David take to the mall? 4. What does David buy his mother? 5. What does David do with the present when he takes it home? 6. Why does David’s mother scream? 7. Why does David buy a spider brooch? 8. Where does David put the present on Christmas Eve?

2018 © Loga - Không Ngừng Sáng Tạo - Bùng Cháy Đam Mê
Loga Team