Recognize that the expression \( (x^2 + 1)^2 \) means you are squaring the binomial \( x^2 + 1 \). This is equivalent to multiplying \( (x^2 + 1) \) by itself: \( (x^2 + 1)(x^2 + 1) \).
Apply the distributive property (also known as FOIL for binomials) to multiply each term in the first binomial by each term in the second binomial: \( x^2 \times x^2 \), \( x^2 \times 1 \), \( 1 \times x^2 \), and \( 1 \times 1 \).