\(P=\left(x^2+2xy\right)^2+2\left(x^2+2xy\right)y^2+y^4\)
\(=x^4+4x^3y+4x^2y^2+2x^2y^2+4xy^3+y^4\)
\(=x^4+y^4+6x^2y^2+4x^3y+4xy^3\)
P = ( x2 + 2xy )2 + 2( x2 + 2xy )y2 + y4
= ( x2 + 2xy )2 + 2( x2 + 2xy )y2 + ( y2 )2
= ( x2 + 2xy + y2 )2
= [ ( x + y )2 ]2
= ( x + y )4
Bài làm :
Ta có :
P = ( x2 + 2xy )2 + 2( x2 + 2xy )y2 + y4
P = ( x2 + 2xy )2 + 2( x2 + 2xy )y2 + ( y2 )2
P = ( x2 + 2xy + y2 )2
P = [ ( x + y )2 ]2
P = ( x + y )4
Vậy P = (x + y)4
\(P=\left(x^2+2xy\right)y^2+2\left(x^2+2xy\right)y^2+y^4\)
\(=\left(x^2+2xy+y^2\right)^2=\left[\left(x+y\right)^2\right]^2=\left(x+y\right)^4\)