设a=48×〖1/(3²-4)+1/(4²-4)……1/(100²-4)〗,则最接近a的正...设a=48×〖1/(3²-4)+1/(4²-4)……1/(100²-4)〗,则最接近a的正整数是 a 18. b20.
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![设a=48×〖1/(3²-4)+1/(4²-4)……1/(100²-4)〗,则最接近a的正...设a=48×〖1/(3²-4)+1/(4²-4)……1/(100²-4)〗,则最接近a的正整数是 a 18. b20.](/uploads/image/z/262849-49-9.jpg?t=%E8%AE%BEa%EF%BC%9D48%C3%97%E3%80%961%2F%EF%BC%883%26%23178%3B%EF%BC%8D4%EF%BC%89%EF%BC%8B1%2F%EF%BC%884%26%23178%3B%EF%BC%8D4%EF%BC%89%E2%80%A6%E2%80%A61%2F%EF%BC%88100%26%23178%3B%EF%BC%8D4%EF%BC%89%E3%80%97%2C%E5%88%99%E6%9C%80%E6%8E%A5%E8%BF%91a%E7%9A%84%E6%AD%A3...%E8%AE%BEa%EF%BC%9D48%C3%97%E3%80%961%2F%EF%BC%883%26%23178%3B%EF%BC%8D4%EF%BC%89%EF%BC%8B1%2F%EF%BC%884%26%23178%3B%EF%BC%8D4%EF%BC%89%E2%80%A6%E2%80%A61%2F%EF%BC%88100%26%23178%3B%EF%BC%8D4%EF%BC%89%E3%80%97%2C%E5%88%99%E6%9C%80%E6%8E%A5%E8%BF%91a%E7%9A%84%E6%AD%A3%E6%95%B4%E6%95%B0%E6%98%AF++++++++++a+18.++++++++b20.)
设a=48×〖1/(3²-4)+1/(4²-4)……1/(100²-4)〗,则最接近a的正...设a=48×〖1/(3²-4)+1/(4²-4)……1/(100²-4)〗,则最接近a的正整数是 a 18. b20.
设a=48×〖1/(3²-4)+1/(4²-4)……1/(100²-4)〗,则最接近a的正...
设a=48×〖1/(3²-4)+1/(4²-4)……1/(100²-4)〗,则最接近a的正整数是 a 18. b20. c24. d25
我要具体解题过程,不好意思
设a=48×〖1/(3²-4)+1/(4²-4)……1/(100²-4)〗,则最接近a的正...设a=48×〖1/(3²-4)+1/(4²-4)……1/(100²-4)〗,则最接近a的正整数是 a 18. b20.
1/(3^2--4)=1/(3^2-2^2)=1/(3+2)*(3-2)=1/1*5
同理,1/(4^2-4)=1/2*6
所以,a=48*(1/1*5+1/2*6+.+1/102*98)
而1/1*5=0.25*(1/1-1/5)
1/2*6=0.25*(1/2-1/6)
将这一结论带入a=48*(1/1*5+1/2*6+.+1/102*98)
并提出0.25再整理即可
答案为25(如果我没算错的话.)