Answer :

Sure, let's factorize the expression [tex]\( a^4 - 1 \)[/tex] step-by-step.

1. Recognize the Difference of Squares:
[tex]\[ a^4 - 1 = (a^2)^2 - 1^2 \][/tex]
This expression is a difference of squares, which can be written as:
[tex]\[ (a^2 - 1)(a^2 + 1) \][/tex]

2. Factorize [tex]\( a^2 - 1 \)[/tex]:
Notice that [tex]\( a^2 - 1 \)[/tex] itself is also a difference of squares:
[tex]\[ a^2 - 1 = (a - 1)(a + 1) \][/tex]

3. Combine All Factors:
Substituting the factorized form of [tex]\( a^2 - 1 \)[/tex] back into the original expression gives:
[tex]\[ a^4 - 1 = (a - 1)(a + 1)(a^2 + 1) \][/tex]

Thus, the fully factorized form of [tex]\( a^4 - 1 \)[/tex] is:
[tex]\[ (a - 1)(a + 1)(a^2 + 1) \][/tex]