In the rectangular coordinate system in the plane, the points A (-2.4), B (4.4) and C (5.3) are given.
Calculate the angle between the lines OB and AC. (The point O is the starting point of the coordinate system.) Round the result to an angular minute.
Write the equation of a circle passing through the points A, B and C. What is the radius of this circle?
Write down the equation of that ellipse with foci A and B passing through the point C. Draw an ellipse in the coordinate system.
