Question

how a4+b4=(a2+b2)^2_2a^2b^2

Answer 1

${x}^{4} + {y}^{4} \\ = ( {x}^{4} + {y}^{4} + 2{x}^{2} {y}^{2} )- 2 {x}^{2} {y}^{2} \\ add \: and \: subtact \: 2 {x}^{2} {y}^{2} \\ = {( {x}^{2} + {y}^{2} ) }^{2} - 2 {x}^{2} {y}^{2} \\ using \: identity \: {(a + b)}^{2}$
let me use x and y instead of a and B
it will be easier to type and will give better understanding