take x=2^(a) then x+(1/x) = 4 then x^2 + 1 - 4x = 0 resolve x = 2 + sqr(3) or x = 2 - sqr(3) But = x=2^(a) -> a=(ln(2+sqr(3)))/ln(2) Or a=(ln(2-sqr(3)))/ln(2)
@dmk_573623 күн бұрын
a=±log₂(2+√3) p.s.log₂(2+√3)+log₂(2-√3) = log₂(4-3) = 0, which also obvious from symmetry of initial equation around zero.
@bernardbaz20037 күн бұрын
A more interesting one would be 2^(a) +2^(-a)=1 (no real solution)
@nigamroy2 ай бұрын
Let 2^a =m Therefore m+1/m=4 m² - 4m +1 =0 Apply Sridhar Acharya equatio m =( 4±√16-4)/2 m= (4±√12)/2 m=(4 ± 2√3)/2 m=2 ± √3 2^a = 2±√3 So a = log(2+√3) of base 2. and a = log (2-√3) of base 2.
@mertuderse1444 күн бұрын
I thought like that also 😂😂😂 he just make that harder and longer
@قدرتاللاهعظیمیعلمداریАй бұрын
Thanks , that was interesting
@charlysanabria393515 күн бұрын
Very well. Thanks.
@b213videoz20 күн бұрын
let x = 2^a x + 1/x = 4 x² + 1 = 4x x² - 4x + 1 = 0 D = 4² - (4 * 1 * 1) = 16 - 4 = 12 x = +/- [4 - sqrt(12)] / 2 Do the rest, I can't be bothered with this tedious drab - typing math formulas on the smartphone while taking a bath is painful 😂 but long story short it boils to: 1) x = 0.26795; 2^a = 0.26795; a = log(0.26795) / 2 2) x = 3.7321 ...do the same, I'm bored 😊 6:03 this was clever...Like
@marcgriselhubert391516 күн бұрын
2^a + 2^(-a) = exp(a.ln(2)) + exp(-a.ln(2)) = 2.Ch(a.ln(2)). So the given equation is equivalent to Ch(a.ln(2)) = 2. It is possible as 2 >= 1 and has two solutions: a.ln(2) = Argch(2) = ln(2 + sqrt(3)) or a.ln(2) = -Argch(2) = -ln(2 + sqrt(3)), (Remind that Argch(x) = ln(x + sqrt(x^2 - 1)) for x>=1) so finally a = ln(2 + sqrt(3)) / ln(2) or its opposite. (This opposite is also equal to ln(2 - sqrt(3)) / ln(2) because ln(2 + sqrt(3)) + ln(2 - sqrt(3) = ln(1) = 0) (The solution ln(2 + sqrt(3)) / ln(2) can also be written log2(2 + sqrt(3)) )
@QwentarАй бұрын
Sometimes with fractions like those, it's easier to multiply the one fraction by 1, in the form of the conjugate of the denominator for a difference of squares. Example: 1/(2+sqrt(3)) isn't nice, we'd rather have a single number in the denominator, not a composite number with square roots. Multiply it by (2-sqrt(3))/(2-sqrt(3)); this is effectively multiplying that one number / fraction by 1 which has no effect on the rest of the equation. You get (1*(2-sqrt(3))/((2+sqrt(3))*(2-sqrt(3))), which gives you (2-sqrt(3))/(4-3)
@قدرتاللاهعظیمیعلمداریАй бұрын
@@Qwentar thank you , for your explanation.
@electricalethertv50415 күн бұрын
Из соображений симметрии, если a - решение, то -a - тоже решение. Таким образом, аффтар не нашел половину решений, следовательно задача не решена. Корректное решение: а=±log₂(2±√3)
@luiscantilloalvarado84446 күн бұрын
❗❗❗❗😃😃💪💪
@RafayKhan-h6q2 ай бұрын
🎉🎉🎉🎉❤😮
@carlosa.correia7938Ай бұрын
beautifull
@momoz7412 күн бұрын
Cool problem, but I have a complaint. Last part is unnecessarily complicated. By definition of the logarithm if 2^a= x then a= log (2) of x. If 2^a = 2+sqrt3 then a = log (2) of (2+sqrt3).
Umm, it's a bit sloppy at the end. You just assume that the second solution works. That is not guaranteed. It needs to be checked.
@fetibayat164Ай бұрын
2üzeri a ya x dersen ikinci derece denklemden kökler 2 eksi 2 kök 3 ve 2 artı 2 kök üç olur 2 üzeri a eşitliğini yap daha kısa sürer
@aristotelesbenicio747615 күн бұрын
too long. why not use base 2 on log directly???
@ludmilak93962 ай бұрын
У меня картинка не работает. Вот такие ответы? а1,2 = log по основанию 2 аргумента (2+ -- (3)^(1/2))
@ENOSKASHIMBA-h7u11 күн бұрын
17 minutes for that simple quetion? give us another method
@raf703729 күн бұрын
Must write X1/2,because is binom
@jenjr803Ай бұрын
好詳細的解法,但解一題需要將近20分鐘,我還是放棄好了
@shazhu245523 күн бұрын
Why don’t you just take log of base 2 in the first place?
@And-Los18 күн бұрын
The correct answer correct answer is: 1) log2(2+sqrt(3)) 2) log2(2-sqrt(3)) 3) -log2(2+sqrt(3)) 4) -log2(2-sqrt(3)) LOOOSER!!!!!
@ももも-h6b11 күн бұрын
you should tell 2^a not equals zero
@ericasi456225 күн бұрын
Неужели обычное квадратное уравнение относительно 2^а достойно быть в разделе олимпиады по математике? Это же школьная программа по алгебре 10-11 класс "показательные уравнения".
@jpf1196 күн бұрын
4=4 OMG
@merwa-mush11 күн бұрын
its good but the clasical sound is disturb
@cantorgauss13 күн бұрын
It’s just a COSH equation.
@jeundyj17 күн бұрын
for middle school??
@miconsta24 күн бұрын
Fun fact: log(2 + √3) + log(2 - √3) = 0
@ILYA1991RUS_Socratus17 күн бұрын
1
@argi0774Ай бұрын
For a = 2 it makes 4 + 1/4 = 4,25. That's close enough, so a = 2.
@surinetso83462 ай бұрын
2^a+2^-a=4 2^a+2^-a=2^2 a+(-a)=2 0=2
@moustaphangandje8642Ай бұрын
2^a + 2^(-a) est différent de 2^ (a+ (-a))
@DinhTrongViet2 ай бұрын
a=0
@Mifodiy19772 ай бұрын
Странно, 17 минут видео. Я в уме решил. Вроде примитивная задача с заменой переменной и логарифмирование.
@CherTTTT2 ай бұрын
Ага зачем тащить 2^а решительно непонятно
@Victurf2 ай бұрын
With this method, we don't know the numerical value of a!
@alexanderizhaki156027 күн бұрын
elegant but not practical
@MrDominicharrison21 күн бұрын
a to the power 0 isn’t 1, it’s a
@guboshlep200823 күн бұрын
Задачку пытался решить математический АЛЕНЬ, попробовал решить, но так и не решил, тяги не хватило.......