Question

factorise this a^4-1

Answer 1

Your answer is ---


${a}^{4} - 1 \: = {a}^{4} - {1}^{4} \\ \\ = {( {a}^{2} )}^{2} - {( {1}^{2} )}^{2} \\ \\ = ( {a}^{2} + 1)( {a}^{2} - {1}^{2} ) \\ \\ = ( {a}^{2} + 1)(a + 1)(a - 1)$


Hope it helps you

Answer 2

$ANSWER \:$

${a}^{4 } - 1 \\ = { {a}^{2} }^{2} - 1 \\ = {( {a}^{2}) }^{2} - {( {1}^{2} })^{2} \\ = ( {a}^{2} - 1)( {a}^{2} + 1) \\ = ( {a}^{2} - {1}^{2} )( {a}^{2} + 1) \\ =( a + 1)(a - 1)( {a}^{2} + 1)$


Thank you