Lesson#2 br Basics of Analytical Geometry br BASIC CONCEPTS br 1. Draw in a plane two mutually prependicular number lines xx and yy, one horizental and the other vertical. br 2. The lines must intersect at real number "0" of both the lines. br 3. The point of intersection is called "origin" and is denoted by "0". br 4. The two lines are called the coordinate axes. br 5. The horizental line x0x is called x-axis. br 6. The x-axis and y-axis has divided the plane into four parts, that are called "QUADRANTS". They are named Q1, Q2, Q3, and Q4. br 7. now there is a point on the plane, through P draw lines parallel to the coordinate axis. MORE..... br chapter No 4 br Introduction to Analytical Geometry br Exercise No 4.