How do you know after you get your answer whether to add 180 or take away 360? And when I learnt this in class i remember having to use a cast graph/table, is this not required with this method?
@@lolvideos5567 It's because of the sine, cosine and tan graphs. He sort of explained it with the sine graph. Basically, for cosine there are two maximum cos values which are found at 0 and 360 degrees so therefore to find all the answers you must take away your answer from 360 first and then you try adding 360 to your original answer to see if it's still within the limits that the question gave you. If you look at the sine graph you'll see that there's only one maximum sine value which is at 180 so therefore you take the answer away from 180. Tan graphs are a bit different and if you have a look at the shape you'll see that when you add 180 to your answer then you'll get the same tan value. In simple terms if your angle came from cos then 360-answer, if it's sin then 180-answer or tan is answer+180. I would highly recommend you find another video solely explaining this as I know for a fact I explained it badly and there is more detail to be added or to ask your teacher as they will be able to answer it much better and give you all the detail you need to fully understand it. Hoped this jogged your memory or at least helped a little bit :)
@@lewispullan6725 do you know why he divides the equation by the hyp on 1:03? I understand that you have to do that but I don't understand the concept behind it. It doesn't make sense to me.
If you're talking about the 1 on the left then that's a +1 and you have to make the equation =0 so you take away the 2 on the right from 1 which gives you -1
@@tanzeenakter8892 there was 1 on left hand side and 2 on right hand side. When you bring the two over to the left hand side it becomes negative. So. 1 - 2 = - 1
Let SIN be squared added to squared COS . Put it mathematically ____ sin²+cos²=1. You cannot add sin together with cos , and end up with 1 . The two have to be squared . Hope that helps.
once you’ve found two solutions when ur solving a sin , you add 360 degrees (or 2pi) onto both answers to find the next ones in . it’s easier to understand if you draw a graph , but essentially it’s because it goes up and down in the y axis , every 180 degrees
@@catalyzt7162 it is because the graph is the same at each side, to work out the other side you can simply take 120 from 360 (hence 240). Taking 360 works too but the sign would be wrong (as it does not go into the negatives for this I guess it would be actually wrong)
easiest method: substitue 1. 5sin(x)=4(sin(x)/cos(x)) 2. 4cos(x)=4sin(x)/5sin(x) 3. cos(x)=0.2/4 4.find x in cos(x) using quadrants then multiply by pi then divide by 180. 5. substitut cos(x)=1/5 in to the equation and workout for sin(x).
![Lp. Сердце Вселенной #30 ДВА В ОДНОМ [Один человек]• Майнкрафт](http://i.ytimg.com/vi/nrXy15orKhY/mqdefault.jpg)
Absolutely Genius way of presentation ----graphics and VoiceOver ---dont change a thing and keep the videos coming!!!!
not me watching this the day before my year 12 maths exam because i don't get trig AT ALL lmaoooo
pleaseeeee got until monday to learn this shit
@@mo3dels163 not to alarm you but mine was dreadful, good luck lmao
me right now ffs
Girlie I’m watching 2 hours before my alevel year 2 exam😭😭💀
@@zainabnawaz4587 omg hey I'm scrolling through tiktok and youtube notifications to avoid last minute revision for mine at 2pm 😍😍 good luck tho
Thank you so much, I have me mock today and had forgotten this
Thank you sm, been struggling with trig for so long
Trig is a pain in the neck lol
For the last one there is an easier method.
1) 5sin(x) - 4tan(x) = 0
2) 5sin(x) = 4tan(x)
3) Then divide all by tan(x)
4) 5cos(x) = 4
5) cos(x) = 4/5
I think the idea is more to show how that identity can be used, not so much the easiest way to do the question overall
u lost some answers
Like YouKnowMeG said, you lose a whole bunch of solutions. ie, where sin(x) = 0
Sooooooo good explanation thank youuuuuuu u r more good than my coaching teachers
@M43k GAMING whom r u referring?
Very helpful, just what I needed!
7:15
i dont think we take -ve sign while doing inverse. we just use it to determine the quadrants(correct me if i am wrong)
thank you so much i have been struggling to submit my assessment but this video really help me. thanks again.
The struggle with trigonometric identities is over . Thank you 🙏
Absolutely genius video, you save my gpa😭
I don’t understand how you factorised @10:45
Why did you add 180 with answer once time but 360-ans the other time? Didn't understand (my exam is in a few hours 😭)
How do you know after you get your answer whether to add 180 or take away 360? And when I learnt this in class i remember having to use a cast graph/table, is this not required with this method?
*take away 180
@@lolvideos5567 It's because of the sine, cosine and tan graphs. He sort of explained it with the sine graph. Basically, for cosine there are two maximum cos values which are found at 0 and 360 degrees so therefore to find all the answers you must take away your answer from 360 first and then you try adding 360 to your original answer to see if it's still within the limits that the question gave you. If you look at the sine graph you'll see that there's only one maximum sine value which is at 180 so therefore you take the answer away from 180. Tan graphs are a bit different and if you have a look at the shape you'll see that when you add 180 to your answer then you'll get the same tan value. In simple terms if your angle came from cos then 360-answer, if it's sin then 180-answer or tan is answer+180. I would highly recommend you find another video solely explaining this as I know for a fact I explained it badly and there is more detail to be added or to ask your teacher as they will be able to answer it much better and give you all the detail you need to fully understand it. Hoped this jogged your memory or at least helped a little bit :)
@@lolvideos5567 Here I think this video of his explains it a lot better than I did ua-cam.com/video/5lu4a_fXq0E/v-deo.html
@@lewispullan6725 thanks alot man Imma check it out
@@lewispullan6725 do you know why he divides the equation by the hyp on 1:03? I understand that you have to do that but I don't understand the concept behind it. It doesn't make sense to me.
If you only have sin without the feta can you still apply the rule sin/cos =tan
how did you get 1/6 pi? what calculation
you have to change the mode of your calculator from degrees to radian.
I don't understand the shift tan(3/4) = 216.9? can anyone help me out??
The calculator says it’s 36.86….
He added 180 degrees cause tan graphs do a full cycle at 180 degrees. They come back to the same y point but with different x points.
where the reciprocal trig identities at
YOU ARE THE BEST
Why do you calculate 360 take away the first answer to get the second answer?
PBsciencetacular he has another video on that I recommend watching it
My teacher taught it in speed and the whole class didn't understand nything including me and maths exam is this week 💀
thank you for the help!
5:14, Where did the other -1 go?
If you're talking about the 1 on the left then that's a +1 and you have to make the equation =0 so you take away the 2 on the right from 1 which gives you -1
Why for sin in radian and for cos in degrees ?
Thank you ao much man, It really helped me out
Easy and fun until i start solving the exercise
Thank so very much sir
Thanks so much!
sorry but 5:06 i dont understand how did 2 become -1 because how did you subtract 2 from the other side when there is nothing to subtract?
1-2=-1
@@justArandomfellar can you please tell me why did it get it subtracted by -1?
@@tanzeenakter8892 there was 1 on left hand side and 2 on right hand side.
When you bring the two over to the left hand side it becomes negative. So. 1 - 2 = - 1
Thank you so much!
why in 11:06 you subtract by pi not 2 pi?
For sin it's - 180 for cosine it's - 360. For tan it's +180
@Mr M lol I commented that so whole ago that now I don't know what it means now! 😂😂 I must've known it back then
@@justArandomfellar tysm
is this for A2 or AS?
As
Thanks so much ❤️💚
Thanks man!
How is sin+cos =1?
Let SIN be squared added to squared COS .
Put it mathematically ____ sin²+cos²=1.
You cannot add sin together with cos , and end up with 1 . The two have to be squared .
Hope that helps.
Well done
anyone know where the 2pi in 18:59 is from?
once you’ve found two solutions when ur solving a sin , you add 360 degrees (or 2pi) onto both answers to find the next ones in . it’s easier to understand if you draw a graph , but essentially it’s because it goes up and down in the y axis , every 180 degrees
@@beccasouthwick so you add 2pi to 0 and pi?
@@marioavilla7680 yes !
6:50 Why did you take away 360 from the answer?
because its on the cos graph which is symetrical
@@WikiPages i have no idea what you said but i'll just minus 360 from the answer
@@catalyzt7162 it is because the graph is the same at each side, to work out the other side you can simply take 120 from 360 (hence 240). Taking 360 works too but the sign would be wrong (as it does not go into the negatives for this I guess it would be actually wrong)
easiest method: substitue
1. 5sin(x)=4(sin(x)/cos(x))
2. 4cos(x)=4sin(x)/5sin(x)
3. cos(x)=0.2/4
4.find x in cos(x) using quadrants then multiply by pi then divide by 180.
5. substitut cos(x)=1/5 in to the equation and workout for sin(x).
Thankyouuuu!
me watching this 15 mins before my mock trying to understand the topic
Thank you sm
thanks a lot
Who comes from cameroon here???
im in year 3 but im so smart im in year 11
Anyone here from bayhouse? Yh thanks Mrs R...