Các câu hỏi tương tự
cho a,b,c,d khac 0 va x=2a^2 +b^2 -2cd; y= 2b^2 +c^2 - 2ad;z=2c^2+d^2-2ab;t=2d^2+a^2-2bc. CMR: trong 4 so x,y,z,t co it nhat 2 so duong
cho 5 so 0,1,2,3,4 tu cac so ay co the lap dc bao nhieu so tu nhien:
a co 5 chu so gom ca 5 chu so ay
b co 4 chu so cac chu so khac nhau
c co 3 chu so cac chu so khac nhau
d co 3 chu so cac chu so co the giong nhau
cmr a^4+b^4+c^4+d^4/b^4+c^4+d^4+e^4=a/e
biết b^2=ac;c^2=bd;d^2=ce
cho a,b,c,d la cac so nguyen duong doi 1 khac nhau thoa man a/a+b + b/b+c + c/c+d + d/d+a =2
CMR abcd la 1 so chinh phuong
cho 4 so nguyen duong a b c dsao cho a2 + b2 = c2+d2 .CMR: tong a+b+c+d la hop so
Cho a,b,c,d la cac so khac 0 va
( a + b + c + d ) . ( a - b - c + d ) = ( a - b + c - d ) . ( a + b - c - d )
CMR : a/c = b/d
Cho x,y,z khac nhau va :1/x+1/y+1/z=1/x+y+z
CMR trong 3 so x,y,z co it nhat 1 cap so doi nhau
Cho cac so a,b,c,d,e,g sao cho a2 + b2 + c2 + d2 + e2=g2
CMR a.b.c.d.e chan
tim a biet a la so co bon so nho nhat chia 5 du 3, chia 7 du 4, chia 9 du 5