 Hi and welcome to our session. Let us discuss a polyquestion. The question says, find the equation of the sphere described on joining the points A and B, having position vectors 2i cap plus 6j cap minus 7k cap and minus 2i cap plus 4j cap minus 3k cap respectively as a diameter. Also find the sector and radius of sphere. First of all, you should know that if the position vectors of the extremities of a diameter of a sphere are vector A and vector B, then its equation is vector R minus vector A dot vector R minus vector B equals to 0. This time its now meeting with the solution and we are given that position vector I mean the R plus 6j cap minus 7k cap equation of the sphere