Để n+3/2n−2 có giá trị nguyên thì n+3⋮2n−2
Ta có n+3⋮2n−2
(n+3)−(2n−2)⋮2n−2
2(n+3)−(2n−2)⋮2n−2
2n+6−2n+2⋮2n−2
8⋮2n−2
2n−2∈ Ư(8)
Ta có : _ Nếu 2n-2=1 2n=3n=1,5
_ Nếu 2n-2=2 2n=4n=2
_Nếu 2n-2=4 2n=6 n=3
_Nếu 2n-2=8 2n=8 n=5
_Nếu 2n-2=-12n=1n=0,5
_Nếu 2n-2=-22n=0n=0
_ Nếu 2n-2=-4 2n=-2 n=-1
_ Nếu 2n-2=-82n=-6 n=-3
Vì n là số tự nhiên n=2 hoặc 3 hoặc 5 hoặc 0
nguồn : cop
Tim so tu nhien n de phan so A=\(\frac{2n+1}{n-3}+\frac{3n-5}{n-3}-\frac{4n-5}{n-3}\)
a/Tim n de A nhan gia tri nguyen
b/Tim n de A la phan so toi gian
Tim so tu nhien n de phan so \(\frac{3n+2}{n-1}\)co gia tri la so nguyen
tim so tu nhien n de phan so n + 3/ 7n + 1 co gia tri la so nguyen
cac banj thong cam may minh ko co dau
bai 1
a, chung to rang 2n+5/n+3, ( n thuoc N ) la phan so toi gian
b, tim gia tri nguyen cua n de B= 2n+5/n+3 co gia tri la so nguyen
bai 2
tim so tu nhien nho nhat sao khi chia cho 3 du 1 cho 4 du 2 cho 5 du 3 cho 6 du 4 va chia het cho 11
1. Cho bieu thuc A=\(\frac{-4}{n-1}\)(voi n\(\in\)Z)
a. So nguyen n phai co dieu Kien gi de A la Phan so
b. Tin cac so nguyen n de A co gia tri nguyen
2. Cho Phan so B= \(\frac{n}{n-4}\)(voi n\(\in\)Z)
a. Tim cac so Nguyen n de B la phan so
b. Tim tat ca cac so nguyen n de B co gia tri nguyen
3. Chung minh rang cac Phan so sau Co gia tri la so tu nhien
a. \(\frac{10^{2016}+2}{3}\)
b.\(\frac{10^{2016}+8}{9}\)
co tat ca bao nhieu so tu nhien n de phan so n+5/n co gia tri so nguyen. So tu nhien n la
co bao nhieu so tu nhien n de phan so \(\frac{n+5}{n}\)co gia tri la so nguyen
Tim so tu nhien de
A=n+10/2n-8 co gia tri la mot so nguyen
tim x nguyen de moi phan so sau do co gia tri la so tu nhien 13/x+3
