Answer :
(a^2+b^2)^2
since (a+b)^2=a^2+2ab+b^2, substitute a with a^2 and b with b^2, which yields:
a^4+2(a^2*b^2)+b^4
since (a+b)^2=a^2+2ab+b^2, substitute a with a^2 and b with b^2, which yields:
a^4+2(a^2*b^2)+b^4
[tex]( a^{2} + b^{2} )^{2}[/tex]
[tex]( a^{2} + b^{2} )( a^{2} + b^{2} )[/tex]
[tex](a^{4}+a^{2}b^{2}+a^{2}b^{2}+b^{4})[/tex]
[tex](a^{4}+2a^{2}b^{2}+b^{4})[/tex]
[tex]( a^{2} + b^{2} )( a^{2} + b^{2} )[/tex]
[tex](a^{4}+a^{2}b^{2}+a^{2}b^{2}+b^{4})[/tex]
[tex](a^{4}+2a^{2}b^{2}+b^{4})[/tex]