A point P moves along the arc of a circle with centre A(2,3). The arc passes through Q(-2,0) and R(5,k).

a) Find i)the equation of the locus of the point P

ii)the value of k

b) The tangent to the circle at point Q intersects(intercepts) the y-axis at point T. Find the area of triangle OQT .

P.S - I'm very weak in locus , anyone can tell me how can I improve it ?