April 23215 BC – A temple is built on the Capitoline Hill dedicated to Venus Erycina to commemorate the Roman defeat at Lake Trasimene. 599 – Maya king Uneh Chan of Calakmul attacks rival city-state Palenque in southern Mexico, defeating queen Yohl Ik'nal and sacking the city. 711 – Dagobert III succeeds his father King Childebert III as King of the Franks. 1014 – Battle of Clontarf: High King of Ireland Brian Boru defeats Viking invaders, but is killed in battle. 1016 – Edmund Ironside succeeds his father Æthelred the Unready as King of England.
Agathocles of SyracuseAgathocles (Ἀγαθοκλῆς, Agathoklḗs; 361–289 BC) was a Greek tyrant of Syracuse (317–289 BC) and self-styled king of Sicily (304–289 BC). Agathocles was born at Thermae Himeraeae (modern name Termini Imerese), Magna Graecia, in Sicily. The son of a potter who had moved to Syracuse in about 343 BC, he learned his father's trade, but afterwards entered the army along with his brother Antander. In 333 BC he married the widow of his patron Damas, a distinguished and wealthy citizen.
TrigonometryTrigonometry () is a branch of mathematics concerned with relationships between angles and ratios of lengths. The field emerged in the Hellenistic world during the 3rd century BC from applications of geometry to astronomical studies. The Greeks focused on the calculation of chords, while mathematicians in India created the earliest-known tables of values for trigonometric ratios (also called trigonometric functions) such as sine. Throughout history, trigonometry has been applied in areas such as geodesy, surveying, celestial mechanics, and navigation.
AortaThe aorta (eɪˈɔrtə ; : aortas or aortae) is the main and largest artery in the human body, originating from the left ventricle of the heart, branching upwards immediately after, and extending down to the abdomen, where it splits at the aortic bifurcation into two smaller arteries (the common iliac arteries). The aorta distributes oxygenated blood to all parts of the body through the systemic circulation. In anatomical sources, the aorta is usually divided into sections.
RadianThe radian, denoted by the symbol rad, is the unit of angle in the International System of Units (SI) and is the standard unit of angular measure used in many areas of mathematics. It is defined such that one radian is the angle subtended at the centre of a circle by an arc that is equal in length to the radius. The unit was formerly an SI supplementary unit and is currently a dimensionless SI derived unit, defined in the SI as 1 rad = 1 and expressed in terms of the SI base unit metre (m) as .
Trigonometric functionsIn mathematics, the trigonometric functions (also called circular functions, angle functions or goniometric functions) are real functions which relate an angle of a right-angled triangle to ratios of two side lengths. They are widely used in all sciences that are related to geometry, such as navigation, solid mechanics, celestial mechanics, geodesy, and many others. They are among the simplest periodic functions, and as such are also widely used for studying periodic phenomena through Fourier analysis.
TriangleA triangle is a polygon with three edges and three vertices. It is one of the basic shapes in geometry. A triangle with vertices A, B, and C is denoted . In Euclidean geometry, any three points, when non-collinear, determine a unique triangle and simultaneously, a unique plane (i.e. a two-dimensional Euclidean space). In other words, there is only one plane that contains that triangle, and every triangle is contained in some plane.
Sine and cosineIn mathematics, sine and cosine are trigonometric functions of an angle. The sine and cosine of an acute angle are defined in the context of a right triangle: for the specified angle, its sine is the ratio of the length of the side that is opposite that angle to the length of the longest side of the triangle (the hypotenuse), and the cosine is the ratio of the length of the adjacent leg to that of the hypotenuse. For an angle , the sine and cosine functions are denoted simply as and .
