Rec is a mathematical operation symbol (finding the point transformation from Polar coordinates to rectangular coordinates), which is opposite to pol. In a calculator, it is generally the transformation of shift+Pol plane coordinates, which transforms points in polar coordinate system into Cartesian coordinate system (that is, plane rectangular coordinate system). For example, the polar coordinate system (r, θ) is transformed into Cartesian coordinate system (x, y).

The result of the calculator conversion operation is the abscissa x of this point. Because the radius of polar coordinates is known, the ordinate y can be obtained by pythagorean theorem. Operation method, for example, rec (8 8,60 60) = 8cos60 = 4. That is Rec(r, θ) = rcos θ.

In a calculator, it is usually necessary to press the "shift" key first and then the "Pol" key to activate the polar coordinate conversion function. This usually opens a new menu or mode that allows you to enter rectangular coordinate values and convert them to polar coordinates. Each calculator may operate in a slightly different way, so it is best to refer to the user manual or online help document of the calculator for accurate guidance.

Characteristics of polar coordinate transformation

First of all, the conversion between polar coordinate system and rectangular coordinate system is usually based on a specific formula. These formulas describe how to convert polar coordinates (r, θ) into rectangular coordinates (x, y) and vice versa.

Secondly, polar coordinate transformation is very useful when dealing with circular symmetry or rotational symmetry. For example, polar coordinates can more easily represent circular or rotationally symmetric shapes and structures. By using polar coordinates, problems involving these shapes can be solved more easily.

In addition, polar coordinate conversion is usually very useful in physics, engineering and mathematics. For example, in electromagnetism, the distribution of current can be described by polar coordinates; In structural engineering, the bending of beams and plates can be analyzed by polar coordinates; Mathematically, polar coordinates can be used to solve some specific differential equations.

Finally, polar coordinate transformation can help us better understand rectangular coordinate system. By studying the transformation between polar coordinates and rectangular coordinates, we can better understand the relationship and difference between the two coordinate systems and have a deeper understanding of the concept of space in mathematics.