Cho a,b,c thỏa mãn
a2010+b2020+c2010=a1005.b1005+b1005.c1005+c1005.a1005
Tính giá trị của A=(a-b)20+(b-c)11+(c-a)2010
Cho a,b,c thỏa mãn:
a2010 + b2010 + c2010 = a1005b1005 + b1005c1005 + c1005a1005
Tính giá trị biểu thức:
A= (a-b)20 + (b-c)11 + (a-c)2010
\(\Leftrightarrow2\left(a^{2010}+b^{2010}+c^{2010}\right)=2\left(a^{1005}b^{1005}+b^{1005}c^{1005}+c^{1005}a^{1005}\right)\)
\(\Leftrightarrow2a^{2010}+2b^{2010}+2c^{2010}-2a^{1005}b^{1005}-2b^{1005}c^{1005}-2c^{1005}a^{1005}=0\)
\(\Leftrightarrow\left(a^{2010}-2a^{1005}b^{1005}+b^{2010}\right)+\left(b^{2010}-2b^{1005}c^{1005}+c^{2010}\right)+\left(c^{2010}-2c^{1005}a^{1005}+a^{2010}\right)=0\)
\(\Leftrightarrow\left(a^{1005}-b^{1005}\right)^2+\left(b^{1005}-c^{1005}\right)^2+\left(c^{1005}-a^{1005}\right)^2=0\)
\(\Rightarrow\left(a^{1005}-b^{1005}\right)^2=0;\left(b^{1005}-c^{1005}\right)^2=0;\left(c^{1005}-a^{1005}\right)^2=0\)
\(\Rightarrow a=b=c\)
\(\Rightarrow\left(a-a\right)^{20}+\left(a-a\right)^{11}+\left(a-a\right)^{2010}=0\)
2 ( a trên 2010 + b trân 2010 + c trên 2010 ) = 2 ( a trên 1005 b trên 1005 + b trên 1005 c trên 1005 + c trên 1005 a trên 1005 )
2a^ ( 2010 ) + 2b^ ( 2010 ) + 2c^ ( 2010 ) - 2a^ ( 1005 ) b^ ( 1005 ) - 2b^ ( 1005 ) c^ ( 1005 ) - 2c^ ( 1005 )a^ ( 1005 ) = O\)
( a^ ( 2010 ) - 2a^ ( 1005 ) b^ ( 1005 ) + b^ ( 2010 ) + ( b^( 2010 ) - 2b^ ( 1005 ) c^ ( 1005 ) + c^ ( 2010 ) + ( c^ ( 2010 ) - 2c^ ( 1005 ) a^ ( 1005 ) + a^ ( 2010 ) = 0\)
( a^ ( 1005 ) ^2 + ( b^ ( 1005 ) - c^ ( 1005 ) ^2 + ( c^ ( 1005 ) - a^ ( 1005 ) - a^ ( 1005 ) ^2 = 0\)
( a^ ( 1005 ) - b^ ( 1005 ) ^ 2= 0 : ( b^ ( 1005 ) - c^ ( 1005 ) ^2 = 0 : ( c^ ( 1005 ) - a^ ( 1005 ) ^2 = 0\)
a = b = c
( a - a ) ^ ( 20 ) + ( a - a ) ^ ( 11 ) + ( a - a ) ^ (2010 = 0\)
Vậy : ( a -a ) ^ ( 20 ) + ( a - a ) ^ ( 11 ) + ( a + a ) ^ ( 2010 = 0\)
1 ) 2(ax2010+bx2010+cx2010)=2(ax1005bx1005+bx1005cx1005+cx1005ax1005)
2ax2010+2bx2010+2cx2010−2ax1005bx1005−2bx1005cx1005−2cx1005ax1005=0
(a2010−2a1005b1005+b2010)+(b2010−2b1005c1005+c2010)+(c2010−2c1005a1005+a2010)=0
Suy ra a=b=c=0
Vậy biểu thức có kết quả là 0
Cho a,b,c thỏa mãn
a2010+b2020+c2010=a1005.b1005+b1005.c1005+c1005.a1005
Tính giá trị của A=(a-b)20+(b-c)11+(c-a)2010
Cho a , b ,c thỏa mãn a^2010 + b^2010 + c^2010 = a^1005.b^1005 + b^1005.c^1005 + c^1005 a^1005 Tính (a - b)^20 + (b - c)^11 + (c - a)^2010
Ta có : a2010 + b2010 + c2010 = a1005b1005 + b1005c1005 + c1005a1005
<=> 2a2010 + 2b2010 + 2c2010 = 2a1005b1005 + 2b1005c1005 + 2c1005a1005
<=> 2a2010 + 2b2010 + 2c2010 - 2a1005b1005 - 2b1005c1005 - 2c1005a1005 = 0
<=> (a2010 - 2a1005b1005 + b2010) + (b2010 - 2b1005c1005 + c2010) + (c2010 - 2c1005a1005 + a2010) = 0
<=> (a1005 - b1005)2 + (b1005 - c1005)2 + (c1005 - a1005 )2 = 0
=> a1005 - b1005 = b1005 - c1005 = c1005 - a1005 = 0
=> a = b = c
Vậy (a - b)20 + (b - c)11 + (c - a)2010 = (a - a)20 + (a - a)11 + (a - a)2010 = 0 + 0 + 0 = 0 .
a2010 + b2010 + c2010 = a1005b1005 + b1005c1005 + c1005a1005
<=> 2a2010 + 2b2010 + 2c2010 = 2a1005b1005 + 2b1005c1005 + 2c1005a1005
<=> 2a2010 + 2b2010 + 2c2010 - 2a1005b1005 - 2b1005c1005 - 2c1005a1005 = 0
<=> (a2010 - 2a1005b1005 + b2010) + (b2010 - 2b1005c1005 + c2010) + (c2010 - 2c1005a1005 + a2010) = 0
<=> (a1005 - b1005)2 + (b1005 - c1005)2 + (c1005 - a1005 )2 = 0
=> a1005 - b1005 = b1005 - c1005 = c1005 - a1005 = 0
=> a = b = c
Cho a , b ,c thỏa mãn a^2010 + b^2010 + x^2010 = a^1005.b^1005 + b^1005.c^1005 + c^1005 a^1005 Tính (a - b)^20 + (b - c)^11 + (c - a)^2010
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Ta có : a2010 + b2010 + c2010 = a1005b1005 + b1005c1005 + c1005a1005
<=> 2a2010 + 2b2010 + 2c2010 = 2a1005b1005 + 2b1005c1005 + 2c1005a1005
<=> 2a2010 + 2b2010 + 2c2010 - 2a1005b1005 - 2b1005c1005 - 2c1005a1005 = 0
<=> (a2010 - 2a1005b1005 + b2010) + (b2010 - 2b1005c1005 + c2010) + (c2010 - 2c1005a1005 + a2010) = 0
<=> (a1005 - b1005)2 + (b1005 - c1005)2 + (c1005 - a1005 )2 = 0
=> a1005 - b1005 = b1005 - c1005 = c1005 - a1005 = 0
=> a = b = c
Vậy (a - b)20 + (b - c)11 + (c - a)2010 = (a - a)20 + (a - a)11 + (a - a)2010 = 0 + 0 + 0 = 0 .
Ta có : a2010 + b2010 + c2010 = a1005b1005 + b1005c1005 + c1005a1005
<=> 2a2010 + 2b2010 + 2c2010 = 2a1005b1005 + 2b1005c1005 + 2c1005a1005
<=> 2a2010 + 2b2010 + 2c2010 - 2a1005b1005 - 2b1005c1005 - 2c1005a1005 = 0
<=> (a2010 - 2a1005b1005 + b2010) + (b2010 - 2b1005c1005 + c2010) + (c2010 - 2c1005a1005 + a2010) = 0
<=> (a1005 - b1005)2 + (b1005 - c1005)2 + (c1005 - a1005 )2 = 0
=> a1005 - b1005 = b1005 - c1005 = c1005 - a1005 = 0
=> a = b = c
Vậy (a - b)20 + (b - c)11 + (c - a)2010
= (a - a)20 + (a - a)11 + (a - a)2010
= 0 + 0 + 0
= 0 .
=> ĐPCM
Cho a, b, c thỏa mãn
a2010 + b2010 + c2010 = a1005b1005 + b1005c1005 + c1005a1005
Tính giá trị của biểu thức :
A = (a - b)20 + (b - c)11 + (c - a)2010
\(a^{2010}+b^{2010}+c^{2010}=a^{1005}b^{1005}+b^{1005}c^{1005}+a^{1005}c^{1005}\)
=>\(2a^{2010}+2b^{2010}+2c^{2010}-2a^{1005}b^{1005}-2b^{1005}c^{1005}-2a^{1005}c^{1005=0}\)
=>\(\left(a^{1005}-b^{1005}\right)\left(b^{1005}-c^{1005}\right)\left(a^{1005}-c^{1005}\right)=0\)
=>a=b=c
\(A=\left(b-b\right)^{20}+\left(b-b\right)^{11}+\left(c-c\right)^{2010}=0\)
cho ba ssos a,b,c thỏa mãn a/2009 = b/2010 = c/2011
tính giá trị của biểu thức : M = 4(a-b)(b-c) - (c-a)^2
cho 3 số a, b, c thỏa mãn; a/2009=b/2010=c/2011. tính giá trị của biểu thức : M= 4(a-b)(b-c)-(c-a)^2
Cho 3 số a,b,c thỏa mãn a+b+c=2010
Tìm số giá trị nhỏ nhất của P=a^2+b^2+c^2
Ta có : \(\left(1+1+1\right)\left(a^2+b^2+c^2\right)\ge\left(a+b+c\right)^2\)(bunhiacopxki)
\(\Leftrightarrow3\left(a^2+b^2+c^2\right)\ge2010^2\)
\(\Rightarrow P=a^2+b^2+c^2\ge\frac{2010^2}{3}=1346700\)
Mình có cách khác giải thích cho bạn chỗ thắc mắc:
Áp dụng BĐT Cô-si:
\(a^2+b^2\ge2ab\)
\(b^2+c^2\ge2bc\)
\(c^2+a^2\ge2ca\)
\(\Rightarrow2\left(a^2+b^2+c^2\right)\ge2\left(ab+bc+ca\right)\)
\(\Rightarrow3\left(a^2+b^2+c^2\right)\ge2\left(ab+bc+ca\right)+a^2+b^2+c^2\)
\(\Rightarrow3\left(a^2+b^2+c^2\right)\ge\left(a+b+c\right)^2\)
1.Cho 3 số a,b,c thỏa mãn :a/2009=b/2010=c/2011
Tính giá trị của M=4(a-b).(b-c)-(c-a)