Hello Nakhi, there are some schools (maybe 5 schools out of every 100 that include the negative). Does your teacher use a negative on the calculator? Then your approach at the end will have to be a little different.
Hello, I do mention this part at 3:40 :) Go check that part again. In summary, no we must not divide by cosx. Rather take everything to one side and then factorise.
MR KEVIN THE compound formula says for sin Sin ( A - B ) = Sin A . Cos B - Cos A . Sin B 1:24 but here I am seeing Sin , Cos , Sin , Cos not Sin , Cos , Cos , Sin So does the order matter?
Hi sir. For the second one, by dividing by cos on both sides i still mamaged to get 30° in the correct quadrants too. I believe this may be a coincidence however would you mind explaining exactly why we cant divide by cos. Pleaseee.
@@6lue6ell78 He is using a different method to that one where I think he's combining both solutions in 1 step. If you did the method that includes both quadrants as separate solutions then yes you would include 270+k.360 as one solution and the other would be 90+k.360
It works with 0,1,-1 and with cos and sin. So if sin = 1 for example. Draw a sin graph. See where it is equal to 1. This would be at 90. Then see how often it repeats that point. This time it would be every 360. So x = 90 + k.360 :)
Yes but when using the special graph method, then it can change. You just need to look at the graph. If you were not using the graph then yes it would be 360 :)
Made trig easy😮Thank you!!
Atleast it is not as "triggy" anymore :) But seriously, glad it helped you!
@@kevinmathscience good one 😂😂
I agree. You made it very easy
Don't be delulu
you couldn't have made it any triggier😂@@kevinmathscience
😂😂😂😂😂😂@@kevinmathscience
5:31 nope sir my teacher did not teach me thank you for highlighting that ❤
Ngiswele amagama okukubonga♡
For question 2, if you use 90+n.360 , would it be wrong?
no😭
why dont you add the minus when working out shift sine of -1/2 on the calculator?
Hello Nakhi, there are some schools (maybe 5 schools out of every 100 that include the negative). Does your teacher use a negative on the calculator? Then your approach at the end will have to be a little different.
3:40 Question 2, could we divide both sides by cosx?
Hello, I do mention this part at 3:40 :) Go check that part again. In summary, no we must not divide by cosx. Rather take everything to one side and then factorise.
Life saver,thank you sm,God bless you!!!
MR KEVIN
THE compound formula says for sin
Sin ( A - B ) = Sin A . Cos B - Cos A . Sin B
1:24 but here I am seeing Sin , Cos , Sin , Cos not Sin , Cos , Cos , Sin
So does the order matter?
5:25 Sir so if it was sin I was going to use 180
And say
X=90 + n . 180
Sir for question 2 is it fine if we use the quadrants 1 and get x=90+k.360;... & Quadrant 4 x=270+k.360;...?
@kevinmathscience is fine if we use this method?
yes
Hi sir. For the second one, by dividing by cos on both sides i still mamaged to get 30° in the correct quadrants too. I believe this may be a coincidence however would you mind explaining exactly why we cant divide by cos. Pleaseee.
I think it's because when you divide you won't find the general solution for cos
Thanks, please do calculus of motion and rates
Noted!
@kevinmathscience sir if I want to use co -function sin2x=-cox
Sin2x=- sin(90-×)
2x= 90-× or 2x=×-90
Which one is correct between two aproch
So if we have this kind of scenario (where cosx=0)we will Only have 90+n.180;nez?? And no other solution?
Yes correct :) Draw the graph. You will see that cosx = 0 at 90 degrees and then every 180 degrees after that :) 90, 270, 450... so on :)
@@kevinmathscience how come we don’t also write the 360-90 +k360 as a solution because cos is also positive in quadrant four?
@@6lue6ell78 He is using a different method to that one where I think he's combining both solutions in 1 step. If you did the method that includes both quadrants as separate solutions then yes you would include 270+k.360 as one solution and the other would be 90+k.360
@@MikiMaeKnox-Davies thank you
don't we normally use 360k ?
We need a face reveal from this man 🙏🙏
Hes already shown his face many times,hes a sexy man
do you use a mouse or a pen when you solve all these questions? i can't imagine how hard it is to use a mouse or a touchpad.
Mr Kevin what happens when you are given this sin2©=cos© and you are required to give general solution?
Sorry sir,couldn't we have just divided -cosx by the cosx from 2sinx.cosx so that we have 2sinx =-½?
For question 2 shouldn't the general solution for cos be +n.360, bcoz we only use 180 if it's tan
Sir , how do you know which questions require a certain kind of approach ?
They will ask determine the general solution
Sir which one do we use? n.360 or k.360😭 I'm confused?
It does not matter just remember KEZ / NEZ
At the end
Sir why don't we include 360-30 in the first one
for question 2 ,is it wrong write +/- 90 + 180k ?
I'm writing in 2.5 hrs😢😂
Idk why we add n.360 thats what confuses me 😢
Sir, is it also the same for other trig ratios? 5:19
It works with 0,1,-1 and with cos and sin.
So if sin = 1 for example. Draw a sin graph. See where it is equal to 1. This would be at 90. Then see how often it repeats that point. This time it would be every 360.
So x = 90 + k.360 :)
Sir, in an exam, how would you know to use this instead of stopping at a certain point?
Isn't cos 360 not 180?
Yes but when using the special graph method, then it can change. You just need to look at the graph.
If you were not using the graph then yes it would be 360 :)
So if l let 6x=x and 12x=2x is it correct
To my understanding yes (I'm also learning)
Wow 😅😁
So easy
Momo trig,🤤