(a⁻¹ + b⁻¹)² - 4a⁻¹b⁻¹

( a ⁻ ¹ + b ⁻ ¹ ) ² - 4 * a ⁻ ¹ * b ⁻ ¹ = ( a ^ ( - 1 ) ) ^ 2 + 2 * a ^ ( - 1 ) * b ^ ( - 1 ) + ( b ^ ( - 1 ) ^ 2 ) - 4 * a ^ ( - 1 ) * b ^ ( - 1 ) = ( a ^ ( - 1 * 2 ) + 2 * a ^ ( - 1 ) * b ^ ( - 1 ) + ( b ^ ( - 1 * 2 ) ) - 4 * a ^ ( - 1 ) * b ^ ( - 1 ) = ( a ^ ( - 2 ) + 2 * a ^ ( - 1 ) * b ^ ( - 1 ) + ( b ^ ( - 2 ) ) - 4 * a ^ ( - 1 ) * b ^ ( - 1 ) = ( a ^ ( - 2 ) + ( b ^ ( - 2 ) ) - 2 * a ^ ( - 1 ) * b ^ ( - 1 ) = a ^ ( - 2 ) + b ^ ( - 2 ) - 2 * a ^ ( - 1 ) * b ^ ( - 1 ) = ( a ^ ( - 1 ) - b ^ ( - 1 ) ) ^ 2.