I would be very interested to learn who invented the reference angle and why they invented it. I've researched the subject and I haven't found any answers yet. Maybe someone here knows the answer.
5:10 This is a random timestamp. Why is the huge angle of [ pi + theta ] being compared to the angle of [ theta in first quadrant ]? Are we just supposed to compare them using the X - Axis? If so, why is this and where did Khan show that?
hey! i hope i understood your question correctly, but here's my best shot at an answer: as you can see at around 5:42, sal writes that sin(-theta) = -sin(theta). this is because sin(theta) is equal to the y-value, and -sin(theta) is equal to the negative of the y-value. that means that sin(-theta) - the angle below the x-axis which has a NEGATIVE y-value - is equal to -sin(theta).
Nothing here is technically incorrect, but it would be less confusing if he would be consistent with where he's putting the negative. (e.g. cos (ɵ) = -cos (π-ɵ)). He switches back and forth. Same difference, but confusing for a new student
@@DivineSeaDragon Yes most people come here because they're oblivious of the topic entirely. Using the color scheme is excellent for both beginners and regulars.
some trig videos uploaded on 3/14, nice one
except it was uploaded yesterday, just in time for today.
waldosan It is published on March 13th, says in the description, could have been uploaded any time before that
I would be very interested to learn who invented the reference angle and why they invented it. I've researched the subject and I haven't found any answers yet. Maybe someone here knows the answer.
The bar in theta is never drawn all the way thru and I keep having to remind myself that they’re not electrons lol
5:10 This is a random timestamp. Why is the huge angle of [ pi + theta ] being compared to the angle of [ theta in first quadrant ]? Are we just supposed to compare them using the X - Axis? If so, why is this and where did Khan show that?
why the value of sin(-theta)= -sin(theta) kindly explain that to me like little ambiguous
hey! i hope i understood your question correctly, but here's my best shot at an answer:
as you can see at around 5:42, sal writes that sin(-theta) = -sin(theta). this is because sin(theta) is equal to the y-value, and -sin(theta) is equal to the negative of the y-value. that means that sin(-theta) - the angle below the x-axis which has a NEGATIVE y-value - is equal to -sin(theta).
@@ohhiitslyd thank you so much dear.
That's soooo much better
Great vid thanks Sal
Nothing here is technically incorrect, but it would be less confusing if he would be consistent with where he's putting the negative. (e.g. cos (ɵ) = -cos (π-ɵ)). He switches back and forth. Same difference, but confusing for a new student
Agreed. That actually confused me at first.
I under stood
1/4 million views and only 200 thumbs up. Bad people. Thanks this video helped.
It's because he didn't remind us to SMASH the like button.
First Comment!!
NO
really? That's pretty cool
Tejas Srirama no that’s pretty gay
@@JMTVTH-cam lol
Anoop Hariharan what r u doing in life rn?
5t
I really don't care about the colors. I think it's a distraction to stop and change colors all the time. Just a thought.
it helps tho :/
Alex T well it helps if you’re new to the whole thing
@@DivineSeaDragon
Yes most people come here because they're oblivious of the topic entirely.
Using the color scheme is excellent for both beginners and regulars.