if `x^4+1=1297` and `y^4-1=2400 `,then `y^2-x^2=`

If x = a +1/a and y=a-1/a then sqrt(x^4+ y^4-2x^2y^2) is equal to : यदि x = a +1/a और y=a-1/a है, तो sqrt(x^4+ y^4-2x^2y^2) का मान किसके बराबर होगा?

If x^(4) + y^(4)=19 and x+y=1 find x^(2)y^(2)-2xy

A circle S cuts three circles x^2 +y^2-4x-2y+4=0 x^2 +y^2-2x-4y+1=0 and x^2 +y^2+4x+2y+1=0 orthogonally. Then the radius of S is