A=$ frac{3}{2}$ - $ frac{5}{6}$ + $ frac{7}{12}$ - $ frac{9}{20}$ + $ frac{11}{30}$ - $ frac{13}{42}$ + $ frac{15}{56}$ - $ frac{17}{72}$ + $ frac{19}

Question

A=$ frac{3}{2}$ - $ frac{5}{6}$ + $ frac{7}{12}$ - $ frac{9}{20}$ + $ frac{11}{30}$ - $ frac{13}{42}$ + $ frac{15}{56}$ - $ frac{17}{72}$ + $ frac{19}{90}$

ngocquynh · Answer

Đ&aacute;p &aacute;n + Giải th&iacute;ch c&aacute;c bước giải:       `A=3/2-5/6+7/12-9/20+11/30-13/42+15/56-17/72+19/90`     `A=(1+2)/(1.2)-(2+3)/(2.3)+(3+4)/(3.4)-(4+5)/(4.5)+...+(9+10)/(9.10)`     `A=1+1/2-1/2-1/3+1/3+1/4-1/4-1/5+...+1/9+1/10`     `A=1+1/10`     `A=10/10+1/10=11/10`

baothah · Answer

`A=3/2-5/6+7/12-9/20 +11/30-13/42+15/56-17/72+19/90`

`⇒A=(1+1/2)-(1/2 + 1/3)+(1/3+1/4)-(1/4+1/4)+(1/5+1/6)-(1/6+1/7)+(1/7-1/9)-(1/8+1/9)+(1/9+1/10)`

`⇒A=1 + 1/2 -1/2 + ……-1/9 + 1/9 + 1/10`

`⇒A=1+1/10`

`⇒A=11/10`

Bình luận

A=$\frac{3}{2}$ – $\frac{5}{6}$ + $\frac{7}{12}$ – $\frac{9}{20}$ + $\frac{11}{30}$ – $\frac{13}{42}$ + $\frac{15}{56}$ – $\frac{17}{72}$ + $\frac{19}

0 bình luận về “A=$\frac{3}{2}$ – $\frac{5}{6}$ + $\frac{7}{12}$ – $\frac{9}{20}$ + $\frac{11}{30}$ – $\frac{13}{42}$ + $\frac{15}{56}$ – $\frac{17}{72}$ + $\frac{19}”

Viết một bình luận Hủy