This circle has the centre at the origin and a radius of 1 unit. The point P can move around the circumference of the circle. At point P the \(x\)-coordinate is \(\cos{\theta}\) and the ...

An animated guide to using trigonometry. Trigonometric terms are explained and examples are used to show how to find unknown angles and sides for right-angled triangles. Use as an introduction or ...

The Pythagorean Theorem—discovered by the Greek mathematician Pythagoras in the 6th century BCE—is a cornerstone of mathematics. Simply stated as a 2 + b 2 = c 2, the theorem posits that the sum of ...

TODHUNTER's “Trigonometry” is a very familiar friend of ours, and we have now before us a bundle of letters which we received from the author in 1861 and 1862, in reply to our criticisms and ...