Related Experiment Video

Updated: Jun 17, 2026

High-resolution Tandem Mass Spectrometry for Studying Chemical Constituents of Gynura bicolor DC
07:16

High-resolution Tandem Mass Spectrometry for Studying Chemical Constituents of Gynura bicolor DC

Published on: February 2, 2024

Constituents of Trigonostemon chinensis

Qin Zhu1, Chun-Ping Tang, Chang-Qiang Ke

  • 1State Key Laboratory of Drug Research & Department of Natural Products Chemistry, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu-Chong-Zhi Road, Zhangjiang Hi-Tech Park, Shanghai 201203, People's Republic of China.

Journal of Natural Products
|December 31, 2009
PubMed

Related Concept Videos

Trigonometry of Right Triangles01:29

Trigonometry of Right Triangles

In a right triangle, trigonometric functions establish specific ratios that describe the relationship between the lengths of the triangle's sides and its acute angles. These relationships are foundational in understanding the structure of right-angled geometry. The sine function quantifies the proportion of the side opposite a given angle compared to the triangle's hypotenuse. In contrast, the cosine function expresses how the side adjacent to the angle relates to the hypotenuse in terms of...
Trigonometric Identities III01:27

Trigonometric Identities III

Cofunction identities are a key concept in trigonometry. They describe how trigonometric functions relate when their input angles are complementary — meaning the angles add up to 90°. On the unit circle, every angle θ— measured counterclockwise from the positive x-axis — corresponds to a point with coordinates (cos⁡ θ, sin ⁡θ). These values represent the horizontal and vertical components of the terminal side of the angle.If the same point on the unit circle is instead described using the...
Trigonometric Functions of Real Numbers01:30

Trigonometric Functions of Real Numbers

The unit circle—a circle with a radius of one, centered at the origin of the coordinate plane—serves as the foundational framework for defining trigonometric functions. In this context, arc length refers to the distance measured along the circumference of the circle between two points, and it provides a way to represent real numbers geometrically. Each real number t corresponds to an arc length measured counterclockwise from the positive x-axis around the circle. The coordinates of a point on...
Trigonometric Equations01:30

Trigonometric Equations

Trigonometric equations involve one or more trigonometric functions and arise frequently in mathematical modeling. These equations may be either identities, which are valid for all values of the variable, or conditional equations, which hold true only for specific values. The process of solving trigonometric equations typically involves both algebraic techniques and the use of fundamental properties of trigonometric functions.Some trigonometric equations resemble standard algebraic forms and...
Trigonometric Identities I01:27

Trigonometric Identities I

Trigonometric identities are equations that relate trigonometric functions and hold for all angles within their domains. A fundamental identity among these is the Pythagorean identity, which arises directly from the geometry of the unit circle. For any angle θ, a point on the unit circle has coordinates (cos⁡ θ, sin ⁡θ), and since the radius of the circle is one, the Pythagorean Theorem gives:This identity serves as the basis for deriving additional identities. Dividing the Pythagorean identity...
Trigonometric Functions: Problem Solving01:19

Trigonometric Functions: Problem Solving

When observing the vertical ascent of an object from a fixed ground position, such as a rocket launch, trigonometric relationships offer a precise method for determining the object's height. As the object rises, an observer stationed at a known horizontal distance from the launch site can measure the angle between the ground and the object's current position. This dynamic angle provides critical information that connects the observed position with its height above the ground.The tangent...