If x = √a + 1, y = √a - 1, then the value of

If x = √a + 1 , y = √a - 1 , then the value of
√a
√a
x⁴ + y⁴ - 2x² y² is

Given in the question ,
x⁴ + y⁴ - 2x² y²
⇒ ( x² - y² )² ⇒ [ ( x + y ) ( x - y ) ]²

⇒

√a +

+ √a -

√a +

- √a +

√a

⇒		2 √a x	2		²	⇒ 16
			√a

If x = √a +	1	, y = √a -	1	, then the value of
	√a		√a