If `A={x^2+y^2=16}` and `B={9x^2+25y^2=225}`, Then `n(AnnB)` is equal to

If A={(x,y):x^2+y^2=25} and B={(x,y):x^2+9y^2=144} then n(Acap B) is

The lenth of the portion of the common tangent to x^(2)+y^(2)=16 and 9x^(2)+25y^(2)=225 between the two points of contact is

The lenth of the portion of the common tangent to x^(2)+y^(2)=16 and 9x^(2)+25y^(2)=225 between the two points of contact is

If x=k is the equqtion of a common tangent to the curves 9x^(2)+16y^(2)=144 ,y^(2)-x+4=0 and x^(2)+y^(2)-12x+32=0 then k is equal to _____

If curves y^2=6x and 9x^2+by^2=16 intersect orthogonally, then b is equal to

Then angle of intersection of the normal at the point (-(5)/(sqrt(2)),(3)/(sqrt(2))) of the curves x^(2)-y^(2)=8 and 9x^(2)+25y^(2)=225 is 0 (b) (pi)/(2) (c) (pi)/(3) (d) (pi)/(4)

Equation of a common tangent to x^(2)+y^(2)=16" and "9x^(2)+25y^(2)=225 is :