Geometry and Trigonometry Overview

Study Notes

Geometry and Trigonometry

Geometry is one of the oldest branches of mathematics, which studies points, lines, surfaces, and their properties. It was developed extensively by ancient civilizations such as Egypt, Babylon, India, Greece, and China. Meanwhile, trigonometry is a branch of mathematics that deals with the relationships between angles and lengths of triangles. Here's an overview of both subjects:

Geometry

Points

In geometry, a point is a location in space without volume. A point is represented with coordinates, which can include either two (x, y coordinates in two dimensions) or three values (x, y, z coordinates in three dimensions). For example, a point can have coordinates like (0, 0) representing the origin, where every straight line away from this point has equal length.

Lines

Lines are used to connect points. They extend infinitely without endpoints, and they can be vertical (parallel to the y-axis), horizontal (parallel to the x-axis), or slanted (forming angles). The distance between any two points along a line is called the segment of the line.

Triangles

Triangles are fundamental shapes in geometry. They consist of three interconnected segments forming polygonal triangles (three sides connected by three vertices). There are different types of triangles, such as equilateral (equal side lengths and angles), isosceles (two sides equal but one angle larger than others), and scalene (all sides unequal).

Trigonometry

Trigonometry is concerned with right triangles, whose sides and included angles satisfy certain properties. It uses ratios involving the sides of the triangle to describe relationships among their angles. Here are some key concepts:

Sine, Cosine, and Tangent

The sine (sin), cosine (cos), and tangent (tan) functions are central to trigonometry. These functions relate to the inner workings of right triangles based on their angles and sides. Specifically, sine is defined as the ratio of the opposite leg of the triangle to the radius of the circle that passes through the hypotenuse. Cosine is defined as the ratio of the adjacent leg to the radius, while tangent is the ratio of the opposite leg to the adjacent leg.

For example, let's consider a right triangle with angles A, B, and C such that angle A is the hypotenuse. Then, we have sin(angle A) = opposite side / radius, cos(angle A) = adjacent side / radius, and tan(angle A) = opposite side / adjacent side.

Trigonometric Identities

There are several identities that hold true for these functions. For example, there is an identity called Pythagorean theorem (sin²x + cos²x = 1), which states that the sum of the squares of the sine and cosine of any angle is equal to one. Another identity is the tangent reciprocal identity (tan(θ) * cot(θ) = 1).

In summary, geometry studies points, lines, surfaces, and their properties, while trigonometry deals with relationships between angles and lengths of triangles. Both subjects are fundamental in mathematics and have various applications in fields like engineering, physics, and computer graphics.

Description

Explore the basics of geometry and trigonometry, including points, lines, triangles, and trigonometric functions such as sine, cosine, and tangent. Learn about geometric shapes, relationships between angles and sides, and essential concepts like Pythagorean theorem and trigonometric identities.