Finding Exact Values of Trig Functions
How to find the exact value of any trig function:
Determine which quadrant the angle is in (sketch the angle if needed)
If it's a quadrantal angle (0, pi/2, pi...), you can easily evaluate it by just drawing a point and plugging in the for the definition of the trig function. (Ex: sin(pi/2) = 1, since at pi/2 x=0, y=1, and r=1)
If it's in the first quadrant, you can easily evaluate it by the table you have memorized.
If it's not in the first quadrant, then find the reference angle. Remember that you can add or subtract any multiple of 2pi to the angle and the value of the trig function at that angle will still be the same. Once you find the reference angle, you can evaluate the function at that angle and then determine if it is positive or negative based on which quadrant the original angle is in.
That's it! Hope this helps!
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Пікірлер: 49
Possibly the very first frat boy to ever become a math teacher
I swear you helped me more in 10 minutes than my teacher in 3 hours!
Sir, I'm from India.This video helped me a lot in understanding this trigonometric topic. I really appreciate your teaching skill..
Take my test for me tmr bro
@BrainGainzOfficial
4 жыл бұрын
hope it went well!
This video is well done. I am a Trigonometry teacher and I need to miss class today. I left this video for my students to watch, so we do not fall behind. Thank you!
I got a B on this exam. Thank you Pink Floyd shirt man
@BrainGainzOfficial
4 жыл бұрын
David Calkins - hell yeah!
This video helped me a TON!! I never connected the dots with reference angles before. Thank you!
Man, this stuff really had me stuck and you just made it click for me. Thanks!
thanks man, been tryna learn this for the past year and i never understood it until i came across this vid
OMG this actually makes sl much sense!
thanks mann this helped so much!!
Would have liked to see some examples with degree measures.
Freakin awesome, thx man
thanks bro, good explaining
Thanks! Helped alot!
@BrainGainzOfficial
5 жыл бұрын
Mark Spelman - Awesome man! Sorry I’m a little behind! More vids coming today and tomorrow! 👍🏼
Most helpful video on this subject, thank you!
Thank u sir it help me a lot
I have a question about two of the examples. For 15pi/4 and 8pi/3, when you said subtract 2pi how did you get to such a simplified version?
@BrainGainzOfficial
Жыл бұрын
Are you asking how I was able to determine 15pi/4 - 2pi and 8pi/3 - 2pi so quickly? The answer is to find a common denominator. For example, 15pi/4 - 2pi = 15pi/4 - 8pi/4 = 7pi/4. I know this is very late, but hopefully this helps other people with the same question.
thanks so much this really helped me!
@missroma1562
4 жыл бұрын
Holly Atkinson R u frm states?
@holly9684
4 жыл бұрын
@@missroma1562 no
@holly9684
4 жыл бұрын
@@missroma1562 nope
@missroma1562
4 жыл бұрын
Thn
@missroma1562
4 жыл бұрын
Btw m frm India
Thank you sir I m from DRC but I live in south Africa you helped me in way I can't explain
Bro whats your workout routine
At 10:15 I got confused. 1/1/2 is = 1/2, not 2 because you multiply the bottom two with each other right? Is there a rule that I don't understand?
@someguy4003
3 жыл бұрын
Think of 1/2 as a decimal. 0.5 , 1 divided by 0.5=2
What about cot(pie)?
This helped a lot but why didn’t you do degrees too?
@BrainGainzOfficial
4 жыл бұрын
radians seem to be more commonly used, but the idea is the same either way.
@herbcruz4697
3 жыл бұрын
In Calculus and other higher-level Math classes, you'll primarily be dealing with radians, as opposed to degrees. If you want to convert your angle from radians to degrees, just take your angle (which is in radians) and multiply it by (180°/pi).
How did u figure out the quadrants I’m confused
@BrainGainzOfficial
4 жыл бұрын
Do you mean how to figure out which quandrant an angle is in? That comes down to being able to sketch the angle. I have a video on it here: kzread.info/dash/bejne/l4GBzK6sk7DVcsY.html - Hopefully that helps. Let me know if you have any more questions.
not sure if explained very clearly or if tattooed math guy caught my attention, but thanks for the help on this one.
gg still too advanced for me damn
Why can’t my professor be like you smh
Excuse me, how do you graph the negative functions so easily? I get confused when I try doing that.
@BrainGainzOfficial
4 жыл бұрын
Start at the ride side of the x axis like you normally would, but then instead of opening up counter clockwise to the angle, open up clockwise. Try it with -3pi/4. You should end up in the same place as 5pi/4. Hope that helps.
Still confused
@BrainGainzOfficial
4 жыл бұрын
Let me know if you have any questions
You're writing the number 4 wrong
Pink Floyd :)
guwapo amp kainspire magaral chos HAHAHAHAHAHAHAHA
i didn't understand anything of what you said im death :(