Grade 12 Trigonometry Lesson 2| Reduction Formulae (More Examples)

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  • เผยแพร่เมื่อ 5 ก.ค. 2024
  • Simplifying trig expressions using reduction formulae. In this video we tackle past exam questions using to help you with more understanding of this section.
    #mlungisinkosi #mathematics #matric

ความคิดเห็น • 99

  • @malefetsanesefehle2869
    @malefetsanesefehle2869 ปีที่แล้ว +29

    I don't want to lie what you're doing father is really helpful I have covered mathematics topics with understanding using this channel thank you sir continue doing the great work father God is with you serious 🤞❤️

  • @Mahlatse1807
    @Mahlatse1807 2 ปีที่แล้ว +25

    Honestly speaking 😭 I'm grateful 🙏 wish I discovered this channel beginning of Term 1

    • @MlungisiNkosi
      @MlungisiNkosi  2 ปีที่แล้ว +2

      We have a bit of marketing work to do…

  • @neoshadi7029
    @neoshadi7029 3 หลายเดือนก่อน +6

    2024 matriculant and ive been struggling but now I understand so well❤❤❤❤, ngiyabonga my favourite uncle😂

  • @keithmaboko1039
    @keithmaboko1039 4 หลายเดือนก่อน +2

    After a decade of passing my matric, I find myself doing grade 12 math and the videos so far are helpful 😊

  • @plaintern2663
    @plaintern2663 2 ปีที่แล้ว +8

    MR N , to add onto your lesson another easy way to find the RATIOS( SIN,COS,TAN), you can put 1 inside the braket to determine the sign, eg Sin(180 -- 1) = positive 0,..... ,AND Sin(180 +1)= NEGATIVE 0,.... the key is to focus on the OUTCOME OF THE SIGN therefore making it easy to identify the quadrant of the RATIO

    • @MlungisiNkosi
      @MlungisiNkosi  2 ปีที่แล้ว +4

      That’s a really nifty trick. I think you should be hired to replace me… Lol

    • @plaintern2663
      @plaintern2663 2 ปีที่แล้ว +2

      @@MlungisiNkosi hahahaha.., i will sleep on it Sir

  • @cozyy.asf_rsa
    @cozyy.asf_rsa 2 ปีที่แล้ว +13

    Yazzzz this 360° when you have a negative angle it is really helping yhooo i didn't even know tht♥️👌👌👌👌

  • @plaintern2663
    @plaintern2663 2 ปีที่แล้ว +15

    Thank you sir your videos have been really helpful, you don't miss!!! 🌑❤️

  • @ziziphobaduza-np3de
    @ziziphobaduza-np3de 9 หลายเดือนก่อน +6

    For the last one my answer is positive 1/8.

  • @victornkgweng4807
    @victornkgweng4807 2 ปีที่แล้ว +12

    🤣360 making things easier thank you 🙏🏼 sir

  • @Roxy_mm2
    @Roxy_mm2 8 หลายเดือนก่อน +1

    Honestly speaking I gave up on writing my p2 tomorrow but looking at ur videos gave me hope

  • @donatella9434
    @donatella9434 ปีที่แล้ว +2

    Thank you so much sir,I can now understand I just need to study and practice now

  • @cozyy.asf_rsa
    @cozyy.asf_rsa 2 ปีที่แล้ว +1

    This is so helpful yhooo sir uu the best teacher😎♥️👌

  • @onishkaramchandar1692
    @onishkaramchandar1692 2 ปีที่แล้ว +1

    extremely helpful,thank you sir

  • @thobilentombela1299
    @thobilentombela1299 2 ปีที่แล้ว +2

    your videos are very helpful. siyabonga!

  • @masindimbulaheni4462
    @masindimbulaheni4462 2 ปีที่แล้ว +1

    Your videos are very helpful,

  • @saidertst3982
    @saidertst3982 ปีที่แล้ว +1

    Mr nkosi we were told that we can use 270^ as it’s not part of the syllabus… on the last example

  • @october.the.4th
    @october.the.4th ปีที่แล้ว +1

    Thank you sir so much😭😭😭you simplified everything for us. But sir can we substitute cos(270-45) such that we have -sin45 instead of cos(180+45)?

  • @refilwenthoroane5705
    @refilwenthoroane5705 หลายเดือนก่อน +2

    Can you please exaplain why cos 270-x isn't (-sinx) and not ( +sinx)

  • @user-zw7jt4ml3h
    @user-zw7jt4ml3h 10 หลายเดือนก่อน +1

    Thank you sir❤🎉

  • @HelenShantelMafudza
    @HelenShantelMafudza หลายเดือนก่อน +1

    For the first example, is the answer not positive 1, since the tangent in the numerator is negative

  • @Thuto_638
    @Thuto_638 2 หลายเดือนก่อน +1

    Sir , at 9:31 ..is it not a +2sinx instead ? because it was -sinx at the top being divided by a -1/2 then when multiplying by 2 at the top and bottom it will then be -2sinx at top then divided by a -1 which would be 2sinx ? pls correct me if I'm wrong 😢.

  • @kamogelomodjadji4005
    @kamogelomodjadji4005 2 ปีที่แล้ว +2

    Greetings to you Sir was asking why dont we also multiply also the -1 that is left out after cancelling the cos

    • @MlungisiNkosi
      @MlungisiNkosi  2 ปีที่แล้ว

      Please provide a time stamp for your question

  • @sarahadem7774
    @sarahadem7774 ปีที่แล้ว +1

    ❤❤

  • @stsnews5125
    @stsnews5125 ปีที่แล้ว +2

    Life saver

  • @iambusang
    @iambusang 2 ปีที่แล้ว +1

    Sir may you please come teach at teneo coz wow your the best only now (today) im understanding and i am more confident about being able to mathematis all this time i felt dom😅

    • @MlungisiNkosi
      @MlungisiNkosi  2 ปีที่แล้ว

      Eish… I can help them if they want me to.

    • @iambusang
      @iambusang 2 ปีที่แล้ว +1

      @@MlungisiNkosi yah sir, please try them. A lot of us there... struggle with mathematics.

    • @MlungisiNkosi
      @MlungisiNkosi  2 ปีที่แล้ว

      @@iambusang sad but it’s a reality 🥹

    • @DitshwaneloMaponopono
      @DitshwaneloMaponopono 4 หลายเดือนก่อน

      ​​@@MlungisiNkosi...Sorry sir for the last example , I found a positive 1/8 because I think that (-) we got when dividing -cos10/cos10 , will affect the whole equation but not sin30 ONLY , or am I wrong sir?

  • @mohaukylie3300
    @mohaukylie3300 ปีที่แล้ว +2

    This has been really helpful ❤️ can you also make a video of solving or evaluating trigonometry in sigma notation questions

  • @yinhlewendy7086
    @yinhlewendy7086 ปีที่แล้ว +1

    please do the past exam papers from 2018,the graphs included November

  • @kwaneleeee3313
    @kwaneleeee3313 2 ปีที่แล้ว +1

    Sir on the last example after cancelling cos10 in the numerator and cos10 in the denominator.
    Why didn't you also cancel Sin 30 and Sin30?
    I don't know if you get me

    • @kwaneleeee3313
      @kwaneleeee3313 2 ปีที่แล้ว +1

      The second sin that which had a negative sign

    • @MlungisiNkosi
      @MlungisiNkosi  ปีที่แล้ว +1

      You may do so

  • @boipelosalome7209
    @boipelosalome7209 2 ปีที่แล้ว +2

    Thanks for this sir ❤❤❤
    But how will I know if I have to make sin(330) to sin(360-30 ) and not sin(270+60) , because they are giving me a different answer. Or I just don't have to use 90 and 270?🤔😢please help me out

    • @boipelosalome7209
      @boipelosalome7209 2 ปีที่แล้ว +2

      Ohoo sorry sir , I got it 😂🤣it is okay to use 270 and 90 just that , that sin will change to its coratio which will be cos60 and cos60 =sin 30 =1/2
      Domkop me😭💔

    • @MlungisiNkosi
      @MlungisiNkosi  2 ปีที่แล้ว +15

      Please don’t call yourself a domkop. I created this channel to prove that you’re not a domkop and if you were, you would not have figured it out

  • @ChunSwaeRrrr
    @ChunSwaeRrrr 2 ปีที่แล้ว +1

    For the last question ,I don't really understand why the sin(270 - 10) became (- cos 10) and not (- cos 80). Isn't like co ratios?

    • @MlungisiNkosi
      @MlungisiNkosi  2 ปีที่แล้ว

      Yes it is co-ratios. Please watch the video before this one

  • @bhekindlovu1034
    @bhekindlovu1034 2 ปีที่แล้ว +1

    hi sir please when you get time teach us how do we change something into co-ratio

    • @MlungisiNkosi
      @MlungisiNkosi  2 ปีที่แล้ว

      I did that… check the earlier lessons

  • @optimisticbeing2740
    @optimisticbeing2740 ปีที่แล้ว +2

    would it be wrong if i expressed cos225 as cos(270 - 225) ? ( at 10:38 )

    • @MlungisiNkosi
      @MlungisiNkosi  ปีที่แล้ว

      Yes that would be incorrect because 270-225 is not equal to 225

  • @michellemoyo3217
    @michellemoyo3217 ปีที่แล้ว +1

    Thank u sir👏🥺

  • @optimisticbeing2740
    @optimisticbeing2740 ปีที่แล้ว +1

    at 3:25, why isn’t it [ 360 - (x - 90 )]? because in lesson 1, we were subtracting from 360 and not adding to it

    • @MlungisiNkosi
      @MlungisiNkosi  ปีที่แล้ว

      We can either add or subtract to get what we are looking for

  • @gao732
    @gao732 ปีที่แล้ว +1

    This is good

  • @nomakhosikhosi5389
    @nomakhosikhosi5389 2 ปีที่แล้ว +1

    Please do Euclidean geometry after trigonometry 😭😭🙏

  • @sparkle38
    @sparkle38 ปีที่แล้ว +1

    Please do negative angles

    • @MlungisiNkosi
      @MlungisiNkosi  ปีที่แล้ว

      Did you check the video after this one?

  • @YibanathiSibembe-cz6bi
    @YibanathiSibembe-cz6bi ปีที่แล้ว +1

    Sir would please provide help on the last question you gave us

  • @user-tw7uo8jn5u
    @user-tw7uo8jn5u 5 หลายเดือนก่อน +1

    Thanks khalhulu babo mlungisi ,I really understand but I am always scared if I'm gonna get an A😢

    • @MlungisiNkosi
      @MlungisiNkosi  5 หลายเดือนก่อน

      You have not been given the spirit of fear. Believe in yourself and the work you have put in. All the best

  • @tamiz3742
    @tamiz3742 ปีที่แล้ว +1

    Night before P2 let’s go

  • @Nothando-om4gr
    @Nothando-om4gr 11 หลายเดือนก่อน

    Since dominators are the same why won't we take them as it is ? Last example sir

  • @pembelanilorah5544
    @pembelanilorah5544 ปีที่แล้ว +1

    Sir I didn't understand step 2 when you were multiplying by negative 1 on the third example

  • @iphithulenyika4412
    @iphithulenyika4412 2 ปีที่แล้ว +1

    Sir in the last question you said -sin 45 instead of -cos45

    • @MlungisiNkosi
      @MlungisiNkosi  2 ปีที่แล้ว +1

      I apologise it an error was made

  • @masindimbulaheni4462
    @masindimbulaheni4462 2 ปีที่แล้ว +1

    Please sir can you do chemistry 🙏

    • @MlungisiNkosi
      @MlungisiNkosi  2 ปีที่แล้ว +1

      Please check under Playlists… there’s everything you need

  • @mahlatseagnes1534
    @mahlatseagnes1534 ปีที่แล้ว +1

    Sir how can sin(270-10) change to cos of 10?🤔

    • @lithembashiceka4072
      @lithembashiceka4072 10 หลายเดือนก่อน

      Because it’s a co-ratio, just check the previous video

  • @euniceledwaba3468
    @euniceledwaba3468 2 ปีที่แล้ว +2

    Good sir. For the first worked example I dont understand, why you changed the cos(270+x) to sin. I know that it might be Co ratios but will I be marked wrong if I don't change it

    • @MlungisiNkosi
      @MlungisiNkosi  2 ปีที่แล้ว +1

      Yes it will be incorrect if you don’t change it

    • @euniceledwaba3468
      @euniceledwaba3468 2 ปีที่แล้ว

      @@MlungisiNkosi okay I wasn't aware of the sir. Thanks.
      But sir may kindly show me more co ratios so that I don't make the same mistake

    • @euniceledwaba3468
      @euniceledwaba3468 2 ปีที่แล้ว

      That **

  • @mandiphiweklaas3034
    @mandiphiweklaas3034 ปีที่แล้ว

    I just don't understand how we get 270

  • @OfentseMongalo
    @OfentseMongalo ปีที่แล้ว +1

    Hi,last example,second step how did you know that sin150 is (180-30) etc

    • @MlungisiNkosi
      @MlungisiNkosi  ปีที่แล้ว

      So you must always try to represent or convert number to (90, 180, 270, 360) and a special angle

    • @OfentseMongalo
      @OfentseMongalo ปีที่แล้ว

      @@MlungisiNkosi ok,thank you.

  • @user-jx4ku8bj6y
    @user-jx4ku8bj6y 8 หลายเดือนก่อน

    Can someone tell me all the special angles😢

  • @aishasibanda5094
    @aishasibanda5094 ปีที่แล้ว +1

    I really don't understand how you get those co-ratios

    • @MlungisiNkosi
      @MlungisiNkosi  ปีที่แล้ว

      I’m not sure what you mean…

    • @aishasibanda5094
      @aishasibanda5094 ปีที่แล้ว

      @@MlungisiNkosi it's good now thank you ..I think I got the hang of it

  • @saidertst3982
    @saidertst3982 ปีที่แล้ว +1

    Mr nkosi we were told that we can use 270^ as it’s not part of the syllabus… on the last example

    • @MlungisiNkosi
      @MlungisiNkosi  ปีที่แล้ว

      But at least you know how to use it in case you get such an example

  • @october.the.4th
    @october.the.4th ปีที่แล้ว +2

    Thank you sir so much😭😭😭you simplified everything for us. But sir can we substitute cos(270-45) such that we have -sin45 instead of cos(180+45)?