Xét tam giác ABC vuông tại A
Áp dụng định lí Pytago, ta đc:
$BC^{2}$=$AB^{2}$ +$AC^{2}$
$BC^{2}$=$6^{2}$+$12^{2}$
BC=6$\sqrt{5}$
Áp dụng tỉ số lượng giác trong tam giác, ta đc
SinB=$\frac{AB}{BC}$ =$\frac{6}{6}$ $\sqrt{5}$
SinB=$\frac{}{5}$ $\sqrt{5}$
B=26độ 33 phút
(VÌ KO CÓ KÍ HIỆU ĐỘ NÊN MÌNH PHẢI VIẾT NHƯ VẬY Ạ)
Đáp án:
Giải thích các bước giải:
Áp dụng định lý Pytago vào ΔABC vuong tại A ta có:
$BC^{2}=AC^2+AB^2$
⇒BC=$6\sqrt5$ cm
Theo định nghĩa tỉ số lượng giác trong tam giác vuông ta có:
sinB=$\frac{AC}{BC}$=$\frac{12}{6\sqrt{5}}$=$\frac{2\sqrt{5}}{5}$
cosB=$\frac{AB}{BC}$=$\frac{6}{6\sqrt{5}}$=$\frac{1}{\sqrt5}$
tanB=$\frac{AC}{BA}$=$\frac{12}{6}$=$2$
cotB=$\frac{AB}{AC}$=$\frac{6}{12}$=$\frac{1}{2}$
IV. Write complete sentences, using the words/ phrases given in their correct forms. 1. Nick/ wash/ hands a lot/ he/ not/ have the flu. 2. David/ eat/ lots of junk food/ he/ not do exercise. 3. doctor/ told Elena that she/ sleep more/ she/ try to relax more. 4. My sister/ play/ computer games/ she does exercise too. 5. Eating/ carrots help/ you see objects / more clearly/ at night. 6. Going outside/ wet hair /give/ you a cold or flu. 7. Eating/ fresh fish/ make/ you smarter
III. Rewrite the sentences without changing the meaning. 1. My brother has fewer friends than my sister My sister ................................................................................................................ 2. My father spends more time going to work than my mother. My mother ............................................................................................................. 3. My mother bought more food than Linh’s mother. Linh’s mother .......................................................................................................... 4. My house has less furniture than Huong’s house. Huong’s house ........................................................................................................ 5. My uncle has more children than my aunt. My aunt .................................................................................................................... 6. I spend more time doing homework than my younger sister does. My younger sister .................................................................................................... 7. Does an apple contain less sugar than a banana? Does a banana ............................................................................................................
Help mình cần gấp ạ nếu phần b làm được thì làm không làm được thì thôi ạ
Cần gấp Phân tích sự liên kết của đoạn văn
II. The word at the end of each of the following sentences can be used to form a word that fits suitably in the blank. 1. Is she enough to run one kilometer? GOOD 2. “Ow! Be careful with that coffee.” - “Look, now I have a BURNING on my arm” 3. Rob has a of 39.50C TEMPERATE 4. Don’t eat so quickly. You’ll get a . TEETH 5. I have a in my back. I’m going to lie down. PAINFUL 6. That’s a bad . Why don’t you have a glass COUGHING of water? 7. “I have .” - “Why don’t you telephone the doctor?” STOMACH 8. I feel . Quick, I must get to the bathroom! SICKNESS 9. My arm after the table tennis match. HURT 10. “I have a .” - “That’s because you watch HEAD too much TV.”
Fill in each blank with a suitable preposition
A= 3+3^2+3^3+...+3^2019 a,thu gọn A b,tìm x thuộc n để 2a+3=3^x
I. Find the word which has a different sound in the underlined part. 1. A. coordinate B. triathlon C. allergy D. calorie 2. A. leaf B. life C. knife D. of 3. A. monopoly B. melody C. compound D. concentrate 4. A. paragraph B. cough C. although D. enough 5. A. vegetarian B. depression C. essential D. attention
rút gọn biểu thức: A=1/√2+1 +1/√3+√2 +1/ √4+ √3 B=1/√1-√2 -1/√2-√3 +1/√3-√4 -1/√4-√5 +...+1/√7-√8 -1/√8-√9
tại sao trẻ sinh đôi cùng trứng đều là nam hoặc đều là nữ
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