Các câu hỏi tương tự
tim 2 phan so co tu = 1, cac mau duong, biet rang tong cua 2 phan so ay cong voi tich cua chung = 1/2
chung to rang tong cua 100 so hang dau tien cua day nho hon 1/4
1/5;1/45;1/117;1/221;1/357;...
cho s=1 phan 11+1 phan 12+1phan13+.....+1phan19+1phan20
chung minh rang 1phan2 lon hon S lon hon 1
chung minh rang tong cua 1 phan so duong voi so nghich dao cua no ko nho hon 2
Khong thuc hien phep tinh de tim ket qua. Hay chung minh rang cac tong sau lon hon 1
N = \(\frac{21}{90}+\frac{31}{72}+\frac{21}{40}+\frac{-1}{45}+\frac{-1}{50}\)
so cac phan so bang -35/28 ma mau cua chung lon hon 1 va nho hon 19
tim tong cac phan so lon hon -1 phan 7 nho hon -1 phan 8 va co tu la-3
Tinh tong bang phuong phap khu lien tiep:
a/ Chung to rang 1/a - 1/a + m = m/a.(a+m)
b/ Tach cac phan so sau thanh hieu cua 2 phan so co tu bang 1:
4/5.9 ; 10/21.31 ; 7/19.26 ; 8/25.33 ; 9/15.24
chung to rang tong B sau lon hon 1/2 B=1/12+1/13+1/14+1/15+1/16+1/17+1/18+1/19+1/20+1/21+1/22