1. The problem statement, all variables and given/known data A is the pt where the circle with wquation x^2+y^2=25 cuts the positive x-axis. Find the midpts of the chords of this circle that contain the pt A 2. Relevant equations 3. The attempt at a solution Since it is about the midpt of chords, I try to set up a equation for the chords: y/x-5 = (√(25 - a^2)) / ((√(25 - b^2) - 5) where (a,b) are the pt on the circle and their ranges are -5<=a<=5 -5<=b<=5 and (x,y) are the pt will fit in the chord Then I used another equation which is perpendicular to the chord and pass through the center of the cirlce (0,0): y/x = (5 - (√(25 - b^2)) / (√(25 - a^2)) Since the intersection of these two pts will be the mid pt of the chord by combining them together it should get the locus. But turn out to be very wired and wrong.... Please help me out! Thx in advance!!