University:
College
Course:
College Mathematics
Academic year:

2022
Views:

261

Pages:

1
Author:

anon

Trigonometry: Right angled trigonometry What is a right-angled triangle? Well basically you should know that it is a triangle with one angle of 90° like the one in Fig.1! Now remember that the 3 angles of a triangle add up to 180°! Also note that in Fig.2 the isosceles triangle is labeled with alphabets! This is the notation that you need to know because many of the coming theorems that you will learn will be expressed in this way! The capital alphabets represent the angles on the triangle and the lower case alphabets represent the length of the side! (Notice that the same letter is given to every angle and its opposite side!) You should already know that: Sin θ = Opposite/Hypotenuse Cos θ = Adjacent/Hypotenuse Tan θ = Opposite/Adjacent A quick way to memorize this is SOH-CAH-TOA. If you don’t know it already, it’s the first letters of each rule!