a^4+ b^4= {( a^2+ b^2)^2-2a^2b^2} proof

LHS:-

a^4+ b^4

＊( a²+ b²)=( a+ b)²- 2ab(this is a square plus b square minus 2 into a into b)

 ( a²)^{^2}+ (b²)^{^2}

 {( a²+ b²)²-  2a²b²

 ( a²+ b²)²-2a²b² proved 

this is read whole suare a square plus b square  minus 2 into a square b square.

x^4+y^4= {( x^2+ y^2)^2-2x^2y^2} proof 

x^4+y^4

 ( x²)^{^2}+ (y²)^{^2}

 {( x²+ y²)²-  2x²y²-x²y²}

 ( x²+ y²)²-2x²y² proved 

this is read whole suare x square plus y square  minus 2 into x square into y square.