14.1 Definition of Sphere14.2 The equation of a sphere with centre at (a, b, c) and radius r14.3 Equation of the Sphere on the Line Joining the Points (x1, y1, z1) and (x2, y2, z2) as Diameter14.4 Length of the Tangent from P(x1, y1, z1) to the Sphere x2 + y2 + z2 + 2ux + 2vy + 2wz + d = 014.5 Equation of the Tangent Plane at (x1, y1, z1) to the Sphere x2 + y2 + z2 + 2ux + 2vy + 2wz + d = 014.6 Section of a Sphere by a Plane14.7 Equation of a Circle14.8 Intersection of Two Spheres14.9 Equation of a Sphere Passing Through a Given Circle14.10 Condition for Orthogonality of Two Spheres14.11 Radical Plane14.12 Coaxal SystemIllustrative ExamplesExercises