Trig Notes

Tuesday’s class: TRIGONOMETRY what is it? literally means “measurement of triangles”, but is actually much cooler than that (see below) trig is a way to connect (and so better to understand) the measurements of line segments and angles can use trig as a tool to figure out angles or sides of triangles which you couldn’t otherwise measure

****** Because similar triangles have proportional sides, the ratios arising from the sides remain constant for a particular angle. Think of all the ratios (fractions) of sides in the following figure of a right triangle:

hypotenuse

opposite

angle A

adjacent

We write sine A =

opposite . hypotenuse

cosecant A =

1 . = sine A

hyp opp

cosine A =

adjacent . hypotenuse

secant A =

1 . cosine A

= hyp adj

tangent A =

opposite adjacent

cotangent A =

1 . tangent A

= adj opp

The three on the left are most important and useful (the ones on the right are just their reciprocals!) so write them down in your notes and work on memorizing them.

Yay!