Cau 1: Chung minh rang cac phan so sau la phan so toi gian voi moi so nguyen?
a, 8n + 5 phan 6n + 4 b, n + 1 phan 2n + 3 c, 2n + 3 phan 3n + 5
Cau 2: Tim tat ca cac so tu nhien n de phan so sau la toi gian
a, n + 13 phan n - 2. b, 18n + 3 phan 21n + 7
Ai giai day du va nhanh thi mk se tick cho
chung to rang cac phan so \(\frac{14n+3}{21n+5}\)va\(\frac{25n+7}{15n+4}\)toi gian voi moi a thuoc Z
chung minh rang moi phan so sau toi gian voi moi so tu nhien n:
a.n+1/2n+3 b.2n+3/4n+8
tim phan so toi gian nho nhat co tu va mau la cac so tu nhien sao cho khi nhan phan so do lan luot voi cac phan so 10/7;5/6;15/9 thi moi tich tim duoc la so tu nhien.
tim phan so toi gian nho nhat co tu va mau la cac so tu nhien sao cho khi nhan phan so lan luot voi moi so \(\frac{10}{7};\frac{5}{6};\frac{15}{9}\)thi moi tich tim duoc la so tu nhien
Chung minh cac phan so sau la phan so toi gian voi moi so nguyen n :A=12n+1 tren 30n+2
chung minh: Voi moi n thi phan so 7n+4/5n+3la phan so toi gian
chung minh rang : Voi moi n thi phan so 7n+4/5n+3 la phan so toi gian .
chung to rang vs moi so tu nhien n , phan so n^3+2n/n^4+3n^2+1 la toi gian
