Geographic coordinates are basically like giving every point on the Earth's surface a 'house number,' mainly determined by longitude and latitude. They treat the Earth as a sphere and use a grid system to tag every place with a unique numeric code. Whether it's the vast ocean or remote mountains and forests, as long as there’s a coordinate, you can pinpoint it accurately.

The Earth does two kinds of movements every day: one is rotating around its axis, and the other is revolving around the Sun, both moving from west to east. Rotation gives us the alternation of day and night, while revolution brings about the changing seasons.

A map is a representation of the Earth's surface on a flat plane, scaled down using symbols according to mathematical rules. It's not just a simple photo, but a geographic model that's been filtered and summarized.

A geometric sequence is a sequence where, starting from the second term, each term divided by the previous term equals the same constant, which is called the common ratio, usually denoted by the letter q.

An equilateral triangle is a triangle where all three sides are of equal length, also called a regular triangle. It's a special kind of isosceles triangle, and all three angles are 60 degrees.

An arithmetic sequence is a sequence where, starting from the second term, the difference between each term and the previous one is the same constant. This fixed difference is called the common difference, usually represented by the letter d. For example, the common odd number sequence 1, 3, 5, 7... has a difference of 2 between each pair of consecutive numbers, which makes it an arithmetic sequence with a common difference of 2.

An isosceles triangle is a triangle that has at least two equal sides. The two equal sides are called the legs, and the other side is called the base. The angle between the legs is called the vertex angle, and the angles between a leg and the base are called the base angles. When solving related problems, if the problem doesn't specify which side is the leg or the base, you usually need to consider different cases.

An isosceles trapezoid is a special type of trapezoid with equal legs. It's a symmetrical shape, with one pair of opposite sides parallel but not equal, and the other pair not parallel but equal in length. It's a common shape you come across when learning geometry.

René Descartes (also often translated as Descartes) was a French philosopher, mathematician, and physicist born on March 31, 1596, and passed away on February 11, 1650. He's commonly called the 'father of modern science.' His most famous quote is 'I think, therefore I am,' and he also invented the Cartesian coordinate system that we often use in math class.

The 'Cartesian network' in math usually refers to an interconnection network built through the Cartesian product of graphs, not the Cartesian coordinate system itself; the latter is often mistakenly called a 'Cartesian network,' but it's actually a 'Cartesian coordinate grid'.