Algebra 2 11.08d - Quadrantal Angles

Quadrantal angles (0, 90, 180, and 270 degrees), and the values of the sine, cosine, and tangent of each of these angles. From the trig lessons in the Algebra 2 course by Derek Owens.

[Janellemarieadams]

This is a WHOLE lot better than what my teacher could've and did explain. Thank you sir.

[cassied]

1:00 - 1:25 gave me my aha moment for quadrantal angles. Thank you.

[bobewell]

thank you so much.You are a thousand times better than my math teacher

[lillypvijey]

Thank you so much. I was searching through so many videos and finally you answered it. God bless you

[kidkid]

Thanks! Helped me right before an exact value quiz.

[adaezeezeani]

Made a lot more sense than what the teacher was explaining

[jemuzu]

THANK YOU . Now im gonna do my best at our recitation tommorow

[tiffanytttang]

This explains so much. Thanks! :')

[EmmalieMorisseau]

Thanks for the video.
Precalc students

[joserulezdd]

ok but what if it's negative? like -180 degrees..

[nfinn]

So my Trig teacher asked the following question in class:  what are the reference angles of angles that lie along the axes of a Cartesian plane?  He assigned this as extra credit for us to research online (so answering me doesn't mean you're helping me cheat, don't worry).

From this video and other sources I've learned that such angles are called Quadrantal angles and do not have reference angles.  But I think he wants more than that.  I think he wants mathematical PROOF that a Quadrantal Angle *cannot* have a reference angle.

Is there a way to formulate this as a mathematical proof?  Or is it just a truism by definition, ie., "Quadrantal angles don't have reference angles because reference angles must be acute" or some such rule?  If so, what is the EXACT, correct and appropriate wording of this rule?

[ullgetown]

what about sin (-270 degree) ? how can i do that one?

[ricardocruzjr.]

how to solve the coordinates of quadrantal angles?

[williamgreen]

Thank you. This video was really helpful!