Ta có :
\(\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.10}+...+\frac{3}{40.43}\)
\(=\)\(\frac{1}{1}-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+...+\frac{1}{40}-\frac{1}{43}\)
\(=\)\(1-\frac{1}{43}\)
\(=\)\(\frac{42}{43}\)
Tính:
3/1.4 + 4/4.7 +3/7.10 + ...+ 3/40.43
3/1.4+3/4.7+3/7.10+.....+3/40.43
tính 3/1.4 + 3/4.7 + 3/7.10 + ... + 3/40.43 + 3/43.46 , rồi giải thích tại sao làm như vậy
A= 3/1.4 + 3/4.7 + 3/7.10 +...+ 3/40.43
3/1.4+3/4.7+3/7.10+................+3/40.43+3/43.47 = ?
e) \(\dfrac{3}{1.4}\)+\(\dfrac{3}{4.7}\)+\(\dfrac{3}{7.10}\)+...+\(\dfrac{3}{40.43}\)
Giải hộ
3/1.4 + 3/4.7 + 3/7.10 + ...... +3/40.43
Phải tính nhanh nha!
Ai nhanh nhất cho 1000000000000000000000000000000000000000000000000000000000000 like luôn!!!!!!!!!!!!!!!
Nhanh nha đang làm đề cương
tính nhanh:
\(\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.10}+.......+\frac{3}{40.43}\)
S=3/1.4 +3/4.7 +3/7.10 +...+3/40.43 +3/43.46
