Unit 1: Intro Trig Flashcards
What is a Reference Angle?
How close/far is the angle from the x-axis in the unit circle
Note: Reference angles are always positive.
What is a Terminal Ray?
What’s between the Reference Angle and the Angle.
A positive angle is drawn…
A positive angle is drawn counter-
clockwise.
A negative angle is drawn…
A negative angle is drawn clockwise.
Two angles are “coterminal” if…
Two angles are “coterminal” if their terminal rays overlap.
Quadrant I is from…
Quadrant I is from 0 to 90 degrees.
Quadrant II is from…
Quadrant II is from 90 to 180 degrees.
Quadrant III is from…
Quadrant III is from 180 and 270 degrees.
Quadrant IV is from…
Quadrant IV is from 270 to 360 degrees.
How to find a coterminal angle?
In order to find a coterminal angle or angles of the given angle, simply add or subtract 360 degrees of the terminal angle as many times as possible.
10 + 360 = 370
10 − 360 = −350
The only correct answer is −350.
How to calculate sin?
How to calculate cos?
How to calculate tan?
SOH CAH TOA on the Unit Circle:
sinθ = y at 0° is…
sin at 0° is 0
SOH CAH TOA on the Unit Circle:
sinθ = y at 30° is…
sin at 30° is 0.5
