\(\frac{3}{2}\)+ \(\frac{7}{6}\)+\(\frac{13}{12}\)+\(\frac{21}{20}\)+\(\frac{31}{30}\)+ \(\frac{43}{42}\)+\(\frac{57}{56}\)+\(\frac{73}{72}\)+\(\frac{91}{90}\)
=\(\frac{3780+2940+2730+2646+2604+2580+2565+2555+2548}{2520}\)
= \(\frac{24948}{2520}\)=\(\frac{99}{10}\)
HỌC TỐT
tính :\(\frac{3}{2}+\frac{7}{6}+\frac{13}{12}+\frac{21}{20}+\frac{31}{30}+\frac{43}{42}+\frac{57}{56}+\frac{73}{72}+\frac{91}{90}\)
Chứng minh rằng : \(\frac{1}{3}+\frac{1}{7}+\frac{1}{13}+\frac{1}{21}+\frac{1}{31}+\frac{4}{43}+\frac{1}{57}+\frac{1}{73}+\frac{1}{91}<1\)
( lời giải chi tiết nha , mình đang cần gấp )
Chứng minh rằng \(\frac{1}{3}+\frac{1}{7}+\frac{1}{13}+\frac{1}{21}+\frac{1}{31}+\frac{1}{43}+\frac{1}{57}+\frac{1}{73}+\frac{1}{91}< 1\)
3/2+7/6+13/12+21/20+31/30+43/42+57/56+73/72+91/90
\(\frac{7}{2}+\frac{7}{6}+\frac{7}{12}+\frac{7}{20}+\frac{7}{30}+\frac{7}{42}+\frac{7}{56}+\frac{7}{72}+\frac{7}{90}\)
3/2+ 7/6 + 13/12 + 21/20 +31/30 + 42/41+ 57/56+ 73/71+ 91/90. mọi ng cho mình lời giải chi tiết vs ạ.
\(\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+\frac{1}{42}+\frac{1}{56}+\frac{1}{72}+\frac{1}{90}+\frac{1}{110}\)
kb với mk nha
\(\frac{3}{2}+\frac{7}{6}+\frac{13}{12}+\frac{21}{20}+...............+\frac{91}{90}+\frac{111}{110}\)
Bài 1:Tìm x,biết:
a)\(\left(\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}\right)\):(x-1,5)=0,25
b)\(\left(\frac{1}{20}+\frac{1}{30}+\frac{1}{42}+\frac{1}{56}+\frac{1}{72}+\frac{1}{90}\right)\)*x-1=\(\frac{101010}{202020}\)
c)\(\left(\frac{1}{11\cdot15}+\frac{1}{15\cdot17}+\frac{1}{17\cdot19}+\frac{1}{19\cdot21}\right)\).924-x=19
Gấp lắm!Giải chi tiết nhé!Mik sẽ tik ai nhanh nhất!^^
