अगर`x^(2)+y^(2)=1`, तब

The locus of the middle point of the chord of the circle x ^(2) + y ^(2) = a ^(2) such that the chords passes through a given point (x _(1) , y _(1)), is : a) x ^(2) + y ^(2) - x x _(1) - y y _(1) =0 b) x ^(2) + y ^(2) = x _(1) ^(2) + y _(1) ^(2) c) x + y = x _(2) + y _(1) d) x + y = x _(1) ^(2) + y _(1) ^(2)

If x ^(2) - 2x ^(2) y ^(2) + 5x + y-5 =0 and y (1) then y '' (1)=