a, Đặt $\left \{ {{u=ln(1-x)} \atop {dv=x.dx}} \right.$
b, Đặt $\left \{ {{u=x} \atop {dv=sin²x.dx}} \right.$
c, Đặt $\left \{ {{u=ln(x+\sqrt[]{1+x}² )} \atop {dv=dx}} \right.$
Cho tam giác ABC có BC = 6cm, AC = 5cm, AB = 4cm, các đường phân giác BD và CE cắt nhau tại I. a) tính AD, DC b) tính tỉ số diện tích của tam giác DIE và tam giác ABC
Biển báo chỉ dẫn có đặc điểm như thế nào ?
Louis Braille was born in France in 1809. His father had a small business. He made shoes and other things from leather. Louis liked to help his father in the store even when he was very small. One day when Louis was 3 years old, he was cutting some leather. Suddenly the knife slipped and hit him in the eye. He soon became completely blind. When he was ten years old, he entered the National Institute for the blind in Paris. One day his class went to visit a special exhibit by a captain in the army. One thing in the exhibit was very interesting for Louis. It showed message in code. Armies send messages in secret codes so no one else can read them. The captain wrote this code in raised letters on very thick paper. Louis thought a lot about this code. Then he decided to write in the same way so the blind could "read" with their fingers. It is very difficult to feel the differences between raised letters. Instead of letters, Louis used a "cell" of six dots. He arranged the dots with two dots across and three down. So blind people can read and write even write music by Braille. 34. Is it difficult to feel the differences between raised letters? ………………………………………………………………………………………………….. 35. How many dots did Louis use instead of letters? …………………………………………………………………………………………………..
Tìm x, y thỏa mãn phương trình: a) x2 - 8x + y2 + 6y + 25=0 b) y2 + 2(x2 + 1) = 2y(x+1)
Giải các phương trình sau : c) ( x+1)(x+9)=(x+3)(x+5) d) (3x+5)(2x+1)=(6x-2)(x-3)
Giải hộ e vs . E cảm ơn (cần ngay hôm nay )
write a letter to your friend to tell him / her about what do you want to do in the future .(100-120 words) Giúp mình nha!!!
Bằng phương pháp hóa học hãy nhận biết các dd sau: a)NaCl, Na2SO4, H2SO4 ,KOH, NaNO3 b)K2S, BaCl2, HNO3, Na2SO4 c)NaCl, K2S, Ba(NO3)2, Ca(OH)2 d) Chỉ dùng quỳ tím nhận biết các chất sau: H2SO4, BaCl2, KOH, AgNO3, NaNO3
làm giàn ý cho đề văn sau : Em sẽ viết ( nói ) gì với các bạn về yêu cầu học nói trong câu tục ngữ quen thuộc : Học ăn , học nói , học gói , học mở ? Làm hộ mình với mình cảm ơn !
Các bạn giúp mình câu 15, 16 nhé Mình sẽ vote 5 sao l
Loga.vn - Cộng Đồng Luyện Thi Trực Tuyến