W-lambert function is not usually on the curriculum in Germany at least. However, you should say in the beginning that you are looking for real solutions, as there are countable many complex ones. So, no you didn't answer your initial question either ;)
Totally agree. Whats the point of solving this problem? Mathematic proficiency can be exercised on problems without the W-lambart. W-lambert is not even a native function on a hp42.
I feel like the triviality of an empirical solution to this particular equation undermines the educational purpose of the video here. When one istrying to showa general solution, one should avoid problems that can be solved almost by reflex, the presence of that easy solution distracts from the general one.
Very complicated methods that totally baffle me. I solved it in 5 seconds simply using arithmetic, what number when squaring 4 gives the same result as multiplying by 8, that number has to be 2 Why make it complicated? 12:25
Use fixed-point or Newton-Raphson iteration. In this case set x←ln(8x)/ln4. In general one or another form of fixed-point iteration may not converge, so it may be necessary to try different forms until finding one that converges. For example, maybe x←(4^x)/8 will converge or from lnx=ln(4^x/8) converted to x←e^{n(4^x/8)} one of these will converge. Complex values for x may also be obtained using fixed-point iteration, but only using complex arithmetic, but most pocket calculators don't support. complex arithmetic.
There are lots of "Collages" in the UK and when I last looked the UK was still part of the European Continent but thankfully no longer ensnared by the EU. Looks like someone funked their Geography lessons.
Painfully slow. If your audience knows what a natural log is you don't need to take 30 seconds to explain you're reversing whats on either side of an equals sign or two minutes to solve basic steps
I really enjoy your videos. But I'd also like to see some problems with differential equations. That would be really interesting.
In this case I'd prefer solving by looking at the equation. 4 squared equals 16 which equals 2 times 8. So x equals 2.
He addresses this in the video, inspection only gives one of the two possible solutions
harald failed 😂😂😂
@@zeldathomas3498-2 is just as intuitive +- pre squaring is a given
W-lambert function is not usually on the curriculum in Germany at least. However, you should say in the beginning that you are looking for real solutions, as there are countable many complex ones. So, no you didn't answer your initial question either ;)
Totally agree. Whats the point of solving this problem? Mathematic proficiency can be exercised on problems without the W-lambart. W-lambert is not even a native function on a hp42.
8:32 forgot to include the 0 to mark the principal root, good vid tho
8x = 4ˣ, x > 0; (8x)¹⸍ˣ = (4ˣ)¹⸍ˣ = 4 = 16¹⸍² = [8(2)]¹⸍²; x = 2
One more root can be obtained using Trial-and-error math:
x = 0: 4ˣ = 4⁰ = 1 > 8(0) = 0; x = 0.5: 4⁰·⁵ = 2 < 8(0.5) = 4; 0.5 > x > 0, Slightly > 0
I feel like the triviality of an empirical solution to this particular equation undermines the educational purpose of the video here. When one istrying to showa general solution, one should avoid problems that can be solved almost by reflex, the presence of that easy solution distracts from the general one.
Exams aren't fair 😂😂
You silly Europeans, you don't write the variable x with two semi-circles, it's two straight lines crossing, just like the letter!
8 2^3 1^1^2 1^2 (x ➖ 2x+1).{ 8x+8x ➖}=16x^2 8^8x^2 2^3^2^3x^2 1^1^1^1^1^1x^2 1x^2 (x ➖ 2x+1).
Very complicated methods that totally baffle me. I solved it in 5 seconds simply using arithmetic, what number when squaring 4 gives the same result as multiplying by 8, that number has to be 2
Why make it complicated? 12:25
Where's the other solution? This isn't a linear equation with a single solution. There's a hidden solution that arithmetic alone won't uncover.
@@jimmycricket7385not sure what u mean. 4 squared = 8x2, that’s it. It’s pure n simple. No other solutions
There are 2 solutions
so in an exam or with only a calculator (not a computer) how do you find the value 0.155
Use fixed-point or Newton-Raphson iteration. In this case set x←ln(8x)/ln4. In general one or another form of fixed-point iteration may not converge, so it may be necessary to try different forms until finding one that converges. For example, maybe x←(4^x)/8 will converge or from lnx=ln(4^x/8) converted to x←e^{n(4^x/8)} one of these will converge.
Complex values for x may also be obtained using fixed-point iteration, but only using complex arithmetic, but most pocket calculators don't support. complex arithmetic.
I got this question in my college assignment 2^x=20 ; find x . Well Most of the students in my college got this wrong including me
@Rishon-n5j x=lg20/lg2=4,3219... .
There are no colleges in Europe. Dismissed.
There are lots of "Collages" in the UK and when I last looked the UK was still part of the European Continent but thankfully no longer ensnared by the EU.
Looks like someone funked their Geography lessons.
What about University College London, and don't gimme no brexit/schmexit?
Yeah bro istg anyone says that doesn’t count the United Kingdom is still in the Continent of Europe
Wish I could hear you !
x=2
I solved this in ¼ second. X=2. A 12 minute video? Smh...
There are 2 solutions.
W(-4ln2*e^(-4ln2))=W(-ln8x*e^(-ln8x)) , -4ln2=-ln8x , 16=8x , x1=2 , W(-ln4/8)=-ln8x , x2=e^(-W(-ln4/8))/8 , x2=~ 0.154953 ,
test x1=2 , 4^2=8*2 , OK , test x2=~ 0.154953 , 4^0.154953=~ 1.23953 , 8*0.154953=~ 1.23953 , same , OK ,
Why Ghanaians solve this in 2 seconds 😊❤🇬🇭🇬🇭🇬🇭🇬🇭🇬🇭🇬🇭🇬🇭🇬🇭🇬🇭🇬🇭❤️❤️♥️🇬🇭💕🇬🇭🇬🇭♥️
And get a fail😂😂😂
I pity you @@ralphhardie7492
2.
Fancy shmancy math
Painfully slow. If your audience knows what a natural log is you don't need to take 30 seconds to explain you're reversing whats on either side of an equals sign or two minutes to solve basic steps
😂
The answer is obvious and can be found by just looking at the equation for 5 seconds.
How to say I didn’t watch the video without saying I didn’t watch the video.
But he told to SOLVE the equation, which means to get ALL the solutions ?
Peter failed 😂😂😂
First 😂
"Cogito ergo sum."@Cartesio