trig notes ref angels

Points and degrees

0/360 - left x origin, 180 - right x origin, 90 top y, 270 bottom y

Ref angles

between terminal ray and x

ref angles quad 1

nothing to it

quad 2

180 - angle

quad 3

angle - 180

quad 4

360 - angle

ASTC counterclock

all letters are POSITIVE for the trig

Special ref angles sin

Sin30 - ½ sin45 - rad2/2, sin60 - rad3/2

cos ref

cos30 - rad3/2, cos45 - rad2/2, cos60 - 1/2

tan ref

tan30 - rad3/3, 45 - 1, 60 - rad3

radian measure to degree

replace pi w 180

degree to radians

multiply by pi/180

coterminal angles

if neg add 360, if positive - 360

reciprocal trig

csc = sin, sec = cos, cot = tan

pythagorean triplets

3-4-5

5-12-13

8-15-17

7-24-25

find recip

decide which quad by seeing the common quad, draw/label tri, find what its asking

sin quadangles

sin0/360 = 0, sin 90 = 1, sin180 = 0, sin270 = -1

cos quadangles

cos0/360- 1, cos90 = 0 , cos180 = -1, cos270 = 0

tan quad angles

0/360= -, 90= undefined, 180 = 0, 270 = undefined