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Math Man Dr. Sam
Registrace 6. 01. 2014
I'm a retired business person and former university professor. Due to covid (and the teacher shortages that followed), I started to help out at our local high school by doing some relief work. Today, I've made school teaching my retirement project. I'm full-time and loving working with the future leaders of our beautiful planet. These videos are created in response to requests from my wonderful students. You folks are amazing! Keep up the great questions and the hard work!
Well solved
🧌
Initial picture is wrong. Lower isosceles triangle has bigger base than the upper one. In order for it to have the same base its vertex angle should be 2arcsin(sin(50)/4), which is approximately 22 degrees instead of 50
Correct. As described in monologue in these vids... Pix are not to scale. Metrics are inaccurate and these do not work. Purpose of vid is only to demo strats for solving as if they did exist, nothing more.
Sorry to inform you Dr Sam but your diagram is impossible to construct. The bottom angle is not 50 degrees but is equal to 22.08 degrees. It may be possible to calculate these things but if the diagram is not correct then the answer is not correct. This is a great example to students of what not to do. Don't assume that the information given to you is correct. Cheers John
Correct. As described in monologue in these vids... Pix are not to scale. Metrics are inaccurate and these do not work. Purpose of vid is only to demo strats for solving as if they did exist, nothing more.
@@mathmandrsam Thank you for the reply. I understand your intention. However you are setting a dangerous prescedent. It would have just as easy to do it correctly the first time. After all you are using an electronic calculator where one number is just as valid as any another. I was in charge of a mechanical design office for 17 years and workshops so I know how things can go off track. Mathematics may be your forte but building things in the real world for over 50 years is mine. Cheers
@@johnspathonis1078 In the words of the great Austin Powers "I like to live dangerously". But, I am also evil. My students all know this and that I leave many mistakes for them to find and correct.
@@johnspathonis1078 However, I note your point. And, if one if my 12-year old students applies for a job at your place of work... don't put them in charge of any important mechanical design project.
@@mathmandrsam I am truly sorry but your students would not pass the entry test. I had the opposite upbringing. About 55 years ago -- my Grade 12 Maths II teacher wrote the text book used by all of Queensland. I answered a question in class and I made a fatal error!!! I disobeyed Isaac Newton’s third law…..“For every action there is an equal but opposite reaction”. For my sins, I had to stand up in class and bow my head in one minute of total silence. May I say one minute is a very long time. I never made that mistake ever again. The problem was this - 10 frictionless identical cylinders (each weight = W) were layered horizontally in a frictionless box. Four (4) cylinders were placed in the bottom layer 1. These cylinders were a close fit inside the box. In layer 2, three (3) cylinders were placed horizontally on top of the four cylinders in layer 1. In layer 3, two cylinders were placed horizontally on top of layer 2. In layer 4, the remaining single cylinder was laid horizontally. So the layers were 4-3-2-1 to form a pyramid shape. The problem is this - In terms of W, calculate all reactions on every cylinder. In summary, I am the product of my environment. As a teacher what sort of environment are you creating? Cheers
Do simultaneuous equation please ♥️
So square roots have functions.. It's not just a rudimentary repeated exercise.. Thia surprises more people than you would think
Hello respected Sir Dr. Sam 🙏 I am also a maths teacher. I like your way of teaching ❤❤ Thank you sir 🙏
LOL I would have used a larger piece of graph paper and a finer pencil for a better estimate, but just looking at your graph, the X intercept of the bottom line is at about +6.25 so slope of rise/run = -7/6.25 = -1.12. As we say in the USA, close enough for government work.
Just keep hitting triple 20 and you are well on the way to winning.
Is this year 10 or year 4 😂
Thank you so much! I finally understand this now, I have been struggling forever!!!! Keep up these videos I have learned so much!! 😁😁👍👍
Hi Sir, I am just a little confused with Q4b in between the second to last and last step at how (2x^2/3 - 1)/5 became (2/5)x^1/3? Should it not be (2/5)x^-1/3?
This is finding the Azimuths. In my Surveying class, Bearings cannot be more than 90 degrees.
√6 is only +√6. To avoid abracadabra with a plus-minus sign, a different approach is needed. One is (x-3)^2 - 6 = (x-3)^2 - (√6)^2 = (x-2 + √6)*(x-2 - √6)=0. The second is, if you have to use the unlucky plus minus sign. √((x-2)^2) = | x-2 |. Then | x-2 | = √6 and solution can bi written as x-2 = ±√6
Thanks brother
Sir, how did you find 262?
Super ducks
You made a mistake in Ex 15.06 x(a+b+c+d) = ax +bx + cx + dx
Good call - will fix when I get a moment 🙂
Thanks teacher
Where do you get the 3 in the first place? To this student it appears you say when x is zero the constant is 3. Where did that come from? Thanks
The constant C is arbitrary since there are a infinite number of curves that would fit the solution. Now in practice you measure it as your initial conditions. For math exercises they give you a point on the desired curve like his example "x=0, f(x)=3."
@@OttoGlassV thank you
Good and helpful lessons
Is this a joke?
No joke - Did I get some of this wrong? Please tell me and I will fix 🙂
bro its 5/7mn^2
Good call! I'll fix
oooppps messed this one up - will redo
I would have simplified the second one to 2x.
Good call!
cool math.
❤❤❤❤❤
Wow, really good😃
Nice!
So is this for grade 8?
Not sure. In NZ students studying this content would be typically 14-15 years old 🙂
algebra is the most useless thing anyone ever came up with and makes no sense .
Good
Doubt: (5,2) is (x,y) so x value = 5 then y value = 2 then why you're put x=2 on the right side instead of 5 .
Good call! I shall schedule this for a re-do 🙂
this video has complelty changed my life and the way i perceive things
Great Video, keep up the great work.
Great Video, keep up the great work.
Great Video, keep up the great work.
really?
Yes! It's true 🙂
Keep up the good work man
Promo_SM
AMAZING VIDEO WOULD RECOMEND
Awesome video, I understand maximum and minimum point better now!! Thank you so much.