fichtean curve

The Keeling curve was drawn by the American scientist Charles David Keeling. Keeling built an observatory in Mauna Loa, Hawaii. Two years after the observatory was built, he published a paper titled Atmospheric CO2 Concentration and Isotopic Abundance, in which he drew the Keeling curve. The curve of the change in the concentration of carbon dioxide observed by Keeling in Mauna Loa was named the Keeling curve, which was considered the most landmark image of climate change science in the 20th century. " The Island of Life " is also a wonderful novel. Everyone is welcome to read it!

From a geometric point of view, the tangents of a curve were straight lines that just happened to touch a point on the curve. When the tangents passed through a point on the curve (the point of tangency), the direction of the tangents was the same as the direction of the point on the curve. From an algebra point of view, in advanced mathematics, if a function had a derivative at a certain point, then the derivative at that point was the slope of the tangency line passing through that point. The straight line formed by the point and the slope was the tangency line of the function. In addition, for a special curve such as a circle, in plane geometry, a straight line that has only one common point with the circle on the same plane is the tangents of the circle. For a general curve, if P and Q are two adjacent points on the curve C, and P is a fixed point, when the point Q is infinitely close to the point P along the curve C, the limit position of the secant line PG is called the tangents of the curve C at the point P, and the point P is called the tangents. The straight line PG that passes through the tangents P and is vertical to the tangents P is called the normal of the curve C at the point P (This reflects the idea of infinite approach). It should be noted that when PT is the tangency of curve C at point P, it may have another intersection with curve C. On the contrary, although the straight line l has only one intersection with curve C, it is not necessarily the tangency of curve C.

In astronomy, the integral curve was a proper term. In the field of mathematics, curve integral was a type of integral. The value of the integral function followed a specific curve (called the integral path). When there was such a concept related to the integral path, it could also be understood as the concept of an integral curve. The curve integral included the first type of curve integral and the second type of curve integral. When the integral path was a closed curve, it was called loop integral or curve integral. In addition, there was also the integral curve defined by the differential equation. The answer could be found from the equation itself. At this time, the properties determined by the equation were qualitative.

Horizontal curve was the general term for the curve at the turning point of the route in the horizontal alignment, including circular curve and transition curve. It was the line connecting two straight lines, allowing the vehicle to transition from one straight line to another straight line.

In a plane graph, a graph composed of curves or a graph composed of curves and straight lines was called a curve graph. For example, a circle was a closed graph surrounded by a smooth curve, and it was a curve graph. For example, if the outline of an irregular figure was mainly composed of curves, it would also be considered a curved figure.