\(F=\dfrac{1}{3}\left(\dfrac{3}{1\cdot4}+\dfrac{3}{4\cdot7}+...+\dfrac{3}{100\cdot103}\right)\)
\(=\dfrac{1}{3}\left(1-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{7}+...+\dfrac{1}{100}-\dfrac{1}{103}\right)\)
\(=\dfrac{1}{3}\cdot\dfrac{102}{103}=\dfrac{34}{103}\)
Tìm a:
A= \(\dfrac{1}{1x4}\)+\(\dfrac{1}{1x7}\)+\(\dfrac{1}{7x10}\)+.....+\(\dfrac{1}{100x103}\)
Tính nhanh:
\(\frac{1}{1x4}+\frac{1}{4x7}+\frac{1}{7x10}+...+\frac{1}{97x100}\)
Mọi người giúp mình bài này với:
Tìm X:
a, X + 5/1x4 + 5/4x7 + 5/7x10 +.............+5/97x100 + 5/100x103 + 5/103x106 = 10
b, X x (9/3x7 + 9/7x11 + 9/11x15+.............+9/91x95 + 9/95x99) = 8
11/1x4+11/4x7+11/7x10+...11/100x103
1/5x9+1/9x13+1/13x17+...+1/2450
mình cần gấp nhé
Tính : 2/1x4+2/4x7+2/7x10+......+2/100x103
A=\(\dfrac{3}{5x8}\)+\(\dfrac{3}{8x11}\)+\(\dfrac{3}{11x14}\)+....+\(\dfrac{3}{100x103}\)
Tính tổng :
\(\dfrac{1}{1.2}+\dfrac{1}{2.3}+\dfrac{1}{3.4}+...\dfrac{1}{2020.2021}+\dfrac{1}{2021.2022}\)
Dấu chấm là dấu nhân
Cho: S=\(\frac{3}{1x4}+\frac{3}{4x7}+\frac{3}{7x10}+...+\frac{3}{100x103}\). Chứng minh S<1
Tính tổng sau : \(\dfrac{1}{2}+\dfrac{1}{6}+\dfrac{1}{12}+\dfrac{1}{20}+\dfrac{1}{30}+\dfrac{1}{42}+\dfrac{1}{56}\)
giúp mik nha, nhớ lm cả lời giải nx nhe. THANK YOU!!!!❤
