Locus of the point, the chord of contact of which subtends an angle `2theta` at the centre of circle `x^2 +y^2 =r^2` is

locus of the middle point of the chord which subtend theta angle at the centre of the circle S=x^(2)+y^(2)=a^(2)

The locus of the point, the chord of contact of which wrt the circle x^(2)+y^(2)=a^(2) subtends a right angle at the centre of the circle is

The locus of the point, the chord of contact of which wrt the circle x^(2)+y^(2)=a^(2) subtends a right angle at the centre of the circle is

If alpha- chord of a circle be that chord which subtends an angle alpha at the centre of the circle. If x+y=1 is alpha -chord of x^(2)+y^(2)=1 , then alpha is equal to

The locus of the point, whose chord of contact w.r.t the circle x^(2)+y^(2)=a^(2) makes an angle 2alpha at the centre of the circle is

The locus of the point, whose chord of contact w.r.t the circle x^(2)+y^(2)=a^(2) makes an angle 2alpha at the centre of the circle is

Locus of the middle points of chords of the circle x^(2)+y^(2)=16 which subtend a right angle at the centre is