(а^2-1)^2= (а^2-1)(а^2-1)= а^4-2а^2+1
(x^2-y^2)^2=(x^2-y^2)(x^2-y^2)=x^4-2x^y^+y^4
(а²-1)²=(a²)²-2*a²*1+1=a⁴-2a²+1
(x²-y²)²=(x²)²-2*x²*y²+(y²)²=x⁴-2x²y²+y⁴
(а^2-1)^2= (а^2-1)(а^2-1)= а^4-2а^2+1
(x^2-y^2)^2=(x^2-y^2)(x^2-y^2)=x^4-2x^y^+y^4
(а²-1)²=(a²)²-2*a²*1+1=a⁴-2a²+1
(x²-y²)²=(x²)²-2*x²*y²+(y²)²=x⁴-2x²y²+y⁴