Các câu hỏi tương tự
1) cho tap hop A={x=a2/a=2k,k thuoc N va 0<a<10} va tap hop B={y thuoc N/y=b^3, b thuoc N}
a)vi\et A va B duoi dang liet ke
b)viet tat ca cac tap hop con cua tap hop A
c)viet tap hop D={x thuoc N/x:64=1} chung to B=D
cac ban co gang giai nhanh giup minh !!thanks
cho a;b thuoc N, a;b khong chia het cho 3 nhung a va b chia cho 3 co cung so du. chung minh ab-1 chia het cho 3
cho a b c thuoc n sao va x+y+z=5; s1= b/a.x+c/a.z;s2=a/b.x+c/d.y;s3=a/c.z+b/c.y Chung minh s lon hon hoac bang 10 voi S=s1+s2+s3
cho A = 1+2+3+4+...+n va B = 2n + 1 ( voi n thuoc N , n lon hon hoac bang 2) chung minh A va B la hai so nguyen to cung nhau
cho a=1+2+3+...+n v b= 2n+1 (voi n thuoc N , n>hoac bang 2 ) . Chung minh rang a va b la 2 so nguyen to cung nhau
cho 2 so nguyen a va b (b khac 0).chung to rang cac cap phan so sau day luon bang nhau: a/-b va -a/b -a/-b va a/b
mong cac ban giup mk
mk cam on
1,tim x,y de x-y=4 va 7x5y2 chia het cho 3
2,a,chung minh so co dang abcabc chia het cho 7,11,13
b,chung minh (a+3)(a+6)/2 la so tu nhien voi a thuoc N
3,a, cho 49 diem thuoc doan thang AB va khong co diem nao trung voi A<B.hoi co bao nhieu doan thang duoc tao thanh tu A,B va 49 diem do.
Chung minh rang voi n thuoc N*, cac phan so toi gian.
a) 3n-2/4n-3 b) 4n+1/6n+1
Lam day du ho minh nhe! Cam on moi nguoi nhieu!
Cho a,b,c thuoc Z sao cho a.b=c.d+1 va a+b=c+d
Chung minh a=b