If `x/y=(a+2)/(a-2)` , then `(x^2-y^2)/(x^2+y^2)` is equal to `(8a)/(a^2+4)` (b) `(4a)/(a^2-4)` (c) `4/(a^2)` (d) `(4a)/(a^2+4)`

If y=(x+3)^(2), then (-2x-6)^(2) is equal to (a)-4y^(2)(b)-2y^(2)(c)-4y(d)2y(e)4y

If x=2,y=1 then x^(4)+2x^(3)y-2xy^(3)-y^(4) is equal to

If x^2+y^2=7 and xy=2 then x^4-2x^2y^2+y^4=

Let y=y(x) be the solution of the differential equation,x((dy)/(dx))+y=x log_(e)x,(x>1) if 2y(2)=log_(e)4-1, then y(e) is equal to: (a)-((e)/(2))(b)-((e^(2))/(2))(c)(e)/(4)(d)(e^(2))/(4)

If sqrt(y)=4x, then (x^(2))/(y) is (a) 2 (b) (1)/(16) (c) (1)/(4) (d) 4

The locus of the middle points of the portions of the tangents of the ellipse (x^(2))/(a^(2))+(y^(2))/(b^(2))=1 included between the axis is the curve (a) (x^(2))/(a^(2))+(y^(2))/(b^(2))=(1)/(4) (b) quad (a^(2))/(x^(2))+(b^(2))/(y^(2))=4 (c) a^(2)x^(2)+b^(2)y^(2)=4 (d) b^(2)x^(2)+a^(2)y^(2)=4

3-8 (2x-y) +4 (2x-y) ^ (2)