Tính: A=(1+7/9)*(1+7/20)*(1+7/33)*..........*(1+7/2900)
Tính nhanh :
A = ( 1 + 7/9 ).(1+7/20).(1+7/33 )....( 1 + 7/2900 )
Tính và so sánh:
a. A= ( 1+7/9)(1+7/20)(1+7/33).............(1+7/2900) với 7
tính
a=(1+(7/9))x(1+(7/20))x(1+(7/33))x...........x(1+(1/2900))
Tính P=(1+7/9).(1+7/20).(1+7/33)...(1+7/2900)
Tính tích :
( 1 + 7/9 ) . ( 1 + 7/20 ) . ( 1 + 7/33 ) ........ ( 1 + 7/2900 )
(1+7/9)x(1+7/20)x(1+7/33)x...x(1+7/2900)
=(8x2)/(9x1) x (9x3)/(10x2) x 10x4/(11x3) x ...x(57x51)/(58x50)
=(8x2x9x3x10x4x...x57x51)x(9x1x10x2x11x3x...x58x50)
Sau khi giản ước ta được:
(8x51)/(1x58)=204/29
mk ko chắc chắn lắm đâu
( 1 + 7/9 ) . ( 1 × 7/20 ) . ( 1 + 7/33 ) ... ( 1 + 7/2900 )
= 16/9 . 27/20 . 40/33 ... 2907/2900
= 2.8/1.9 . 3.9/2.10 . 4.10/3.11 ... 51.57/50.58
= 2.3.4...51/1.2.3...50 . 8.9.10...57/9.10.11...58
= 51 . 8/58
= 204/29
1-tính tích
p=(1+7/9)(1+7/20)(1+7/33)...(1+7/2900)
Ta có :( 1 + 7/9 ) x ( 1 + 7/20 ) x ( 1 + 7/33 ) x...x ( 1 + 7/2900)
= (8x2)/(9x1) x (9x3)/(10x2) x (10x4)/(11x3) x...x (57x51)(58x50)
=(8x2x9x3x10x4x...x57x51) / (9x1x10x2x11x3x...x58x50)
Sau khi giản ước ta được :
= (8x51) / (1x58) = 204/29
(1+7/9)*(1+7/20)*(1+7/33)*...*(1 + 7/2900) = ?
chứng minh rằng :(1+7/9)(1+7/20)(1+7/33).......(1+7/2900)=7 1/29
\(\text{ P = (1 + \dfrac{7}{9}) (1 + \dfrac{7}{20}) (1 + \dfrac{7}{33})….(1 + \dfrac{7}{2900})}\)