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`

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

Find the locus of the middle points of the chords of the parabola y^2=4a x which subtend a right angle at the vertex of the parabola.

Find the locus of the middle points of the chords of the parabola y^2=4a x which subtend a right angle at the vertex of the parabola.

Find the locus of the middle points of the chords of the parabola y^2=4a x which subtend a right angle at the vertex of the parabola.

Find the locus of the middle points of the chords of the parabola y^2=4a x which subtend a right angle at the vertex of the parabola.

Find the locus of the middle points of the chords of the parabola y^2=4a x which subtend a right angle at the vertex of the parabola.

Find the locus of the middle points of the chords of the parabola y^2=4a x which subtend a right angle at the vertex of the parabola.

Find the locus of the middle points of the chords of the parabola y^(2)=4ax which subtend a right angle at the vertex of the parabola.

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