六年级奥数题49+1/49-1+81+1/81-1+121+1/121-1+.9800+1-9800-1等于多少

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六年级奥数题49+1/49-1+81+1/81-1+121+1/121-1+.9800+1-9800-1等于多少六年级奥数题49+1/49-1+81+1/81-1+121+1/121-1+.9800+

六年级奥数题49+1/49-1+81+1/81-1+121+1/121-1+.9800+1-9800-1等于多少
六年级奥数题49+1/49-1+81+1/81-1+121+1/121-1+.9800+1-9800-1等于多少

六年级奥数题49+1/49-1+81+1/81-1+121+1/121-1+.9800+1-9800-1等于多少
49+1/49-1+81+1/81-1+121+1/121-1+.9801+1/-9801-1
=1+2/6*8+1+2/8*10+1+2/10*12+……+1+1/98*100
=47+(1/6-1/8+1/8-1/10+1/10-1/12+……+1/98-1/100)
=47+(1/6-1/100)
=47又47/300

0

10

(49+1)/(49-1)+(81+1)/(81-1)+(121+1)/(121-1)+....(9801+1)/(9801-1)
=1+2/(6*8)+1+2/(8*10)+1+2/(10*12)+...+1+1/(98*100)
=93+(1/6-1/8+1/8-1/10+1/10-1/12+...+1/98-1/100)
=93+(1/6-1/100)
=27947/300