" (d) "x^(2)+y^(2)=sqrt(2)a^(2)" And "x^(2)-y^(2)=u^(2)

Simplify : (sqrt(x^(2)+y^(2))-y)/(x-sqrt(x^(2)-y^(2))) div (sqrt(x^(2)-y^(2))+x)/(sqrt(x^(2)+y^(2))+y)

u=(x^(2)-y^(2))/(x^(2)+y^(2)) find d(u)/(dx)?

Simplify : (sqrt(x^(2)+y^(2))-y)/(x-sqrt(x^(2)-y^(2)))-:(sqrt(x^(2)-y^(2))+x)/(sqrt(x^(2)+y^(2))+y)

Simplify : (sqrt(x^(2)+y^(2))-y)/(x-sqrt(x^(2)+y^(2)))-:(sqrt(x^(2)+y^(2))+x)/(sqrt(x^(2)+y^(2))+y)

Equation of a line which is tangent to both the curve y=x^(2)+1 and y=x^(2) is y=sqrt(2)x+(1)/(2) (b) y=sqrt(2)x-(1)/(2)y=-sqrt(2)x+(1)/(2)(d)y=-sqrt(2)x-(1)/(2)

x+y(dy)/(dx)=sec(x^(2)+y^(2)), where x^(2)+y^(2)=u

Rationalise the denominator: (a) (1)/(root(3)(3) + root(3)(2)) , (b) (2)/(sqrt5 + sqrt3 + sqrt2) , (c) (x^(2))/(sqrt(x^(2) + y^(2)) - y) , (d) (1)/(sqrt6 + sqrt5 - sqrt11) (e) (sqrt(x + 2y) - sqrt(x -2y))/(sqrt(x + 2y) + sqrt(x - 2y)) , (f) (sqrt10 + sqrt5 - sqrt3)/(sqrt10 - sqrt5 + sqrt3)

If u=log(x^(2)+y^(2)+z^(2)) prove that (del^(2)u)/(del x^(2))+(del^(2)u)/(del y^(2))+(del^(2)u)/(del z^(2) = 2/(x^(2)+y^(2)+z^(2)

The equation sqrt([(x-2)^(2)+y^(2)])+ sqrt([(x+2)^(2)+y^(2)])=4