Even and Odd Trigonometric Functions & Identities - Evaluating Sine, Cosine, & Tangent

This trigonometry video explains how to use even and odd trigonometric identities to evaluate sine, cosine, and tangent trig functions. This video contains plenty of examples and practice problems.

The Unit Circle:

How To Remember The Unit Circle Fast:

Reference Angles:

The Six Trigonometric Functions:

How To Solve Right Triangles:

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Reciprocal Identities:

Quotient Identities:

Pythagorean Identities:

The Pythagorean Theorem:

Trig Functions - Periodic Properties:

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The Exact Value of Trig Functions:

Special Right Triangles - 30 60 90:

Special Patterns - Pythagorean Theorem:

Cofunction Identities:

Final Exams and Video Playlists:

Full-Length Videos and Worksheets:

Trigonometry Formula Sheet:

[Motiongang_]

You are literally a messenger for our generation in the aid of all subjects, may god bless you.

[shadrachhamner]

5:03 I think you may have made an error in saying that quadrant 2 has a positive x value and a negative y value. While cosine (x) value is going negative the sine (y) value remains about the x axis. Therefore it is positive

[georgesadler]

MR. Organic Chemistry Tutor, that you for showing examples of Even and Odd Trigonometry Functions. These videos are outstanding for all students in mathematics, engineering and physics.

[bekaabate]

your tutrials are saving my grades, what you are doing is great, and thank you. i started learning fourier series last week and i can't find any videos you made on the topic, can you make videos on the topic please

[artahighmore]

At 4:30 the answer is positive one as he mentioned at 5:51 because in third Q cos and sin are both negative

[thiruselvamm]

In 4.55 quadrant 2 X is negative Y is positive(-, +)

[aaronius]

Thank you bro. Much love, I'm taking Trig right now this summer and I'm taking Calc 3A and 3B in the Fall and next Summer. Wish me luck!! Regning from the Bay is where I stay.

[cindysextonfl]

In quadrant 2, you said (4:58) that X is positive & Y is negative. This is not correct. To the left of the X, Y intersect (0) on the # line, X becomes negative. The Y axis is still positive because it is above the X axis.

[sanopann]

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[cerealbeforemilk]

Thank you for your videos, they are super helpful

[sylviawang]

At 4:31, the diagram, shouldn't the -3pi/4 be in the 3nd quadrant? since -3pi/4 is equal to -135.

[hassaanahmedkhan]

Your videos are great but please increase audio level

[blackchild]

are sure you did not make mistake on 5:03 when you said x is positive y is negative please respond, your response will highly appreciated

[carlwur]

Why at 5:02 in the video do you say in QII x is positive and y in negative?

[timsambaker]

can somebody help me understand why cos(-x) is equal to cos(x) while sin(-x) is equal to -sin(x)? if im looking at the graph it is pretty straightforward that cosine graph is even however the algebra part confuses me. why is it cos(-x) is not equal to -cos(x)?

[JohnB-ufft]

At 501 he says something wrong. He says that in Quad two, x is positive and y is negative WRONG! X is negative and y is positive. He messed up. Someone ask him to re do the video or he could confuse someone.

[Dr.JudeAEMasonMD]

Can somebody please reinvent circle geometry 📐 in terms of ז radians? Please.

[ghaintsingh]

Thanks so much teacher I m from india Punjab you save my alot of time 🙏

[nikitaavontuur]

Sir how do you manage get the coordinates for those angles ?

[jasonstanley]

Hello, I am confused about the quadrant location in 5pi/6, shouldn't the positive 5pi/6 be in the same quadrant as pi/6, which is 1, and the -5pi/6 should be in quadrant 3, if you start from pi and go counterclockwise for positive, it would be pi/6, 2pi/6, 3pi/6, 4pi/6 and then 5pi/6, wouldn't it? well I guess that wouldn't make much sense when you got to 6pi/6 because that is just pi and that is the negative x part of the graph, so how do you really count the radians ? They should each have a variation of pi/6, pi/4, pi/3 in each quadrant and not multiples of these, shouldn't they? I am confused on that part..