this lambert W function feels like a cheat code.
I don't think anyone is learning the Lamber function in high school. Therefore not sure this would be on any college entrance exam.
There is no Harvard Entrance Exam and no need to reference the Lambert W function. The solution is between 3 and 4. Just take the log of each side : t log t=2log 7. Then use a couple of iterations of Newton's method to solve: t=(t+2*log(7))/(1+log(t)). Solution is approximately 3.278031523596059
I, lacking any Calculus skills, use the "Artillery" method. T^t = 49 3³ = 27 4⁴ = 256 I have now "bracketed" the range, within which is the target. Now we just increase the minimum range (3) by tenths: 3.2^3.2 = 41.35 3.3^3.3 = 51.42 This is the new bracket, we then adjust our estimations by hundredths: 3.27^3.27 = 48.15 3.28^3.28 = 49.21 We then continue finding each range, and increasing the next decimal until we derive adequate accuracy required by the question. 😊
3^3=27 (low) 4^4=256 (high) 3.5^3.5 (high) 3.25^3.25 (low) 3.275^3.275 (low) 3.28^3.28 (high) 3.2775^3.2775 (low).... quickly got to ~3.2781, but could keep going for more accuracy
My dumbass really thought 7⁷ =49 .
Please use ln instead off log as log with no base is used for base 10
To solve \(T^T = 49\), take natural log on both sides: \(T \ln T = \ln 49\). Since \(\ln 49 ≈ 3.8918\), solve \(T \ln T = 3.8918\). This transcendental equation gives \(T ≈ 3.3\) as the approximate solution. Exact value needs numerical or graphical methods.
There are dozens of videos similar to this where the solution is always the W function. They're trying to make the W function into one of the primary functions, such as ln, exp, sin, cos, etc. But one could always create a problem for which a Jessel function is the solution. If you do it over and over, then you can prtend like Jessel functions should be included in the list of primary functions.
0:39 4^4 is not 64!
pls use ln() since log is mostly used for 10 asw edit: i read about it more and found out log(x) has many bases including e, 10 and 2 - comp science uses 2 since binary has 2 digits - higher levels of maths / physics mostly use base e - highschool math & chem use base 10 (e.g when calculating pH) and many calculators have log(x) as base 10 tldr; the meaning of log depends on the application/context, but using ln() makes it more clear (esp for high school students)
This would have more value to more people if you explained the basics of the steps you took to solve it.
OR you can use the well known Wilson L function, the main property of which is L(x^x) = x. Which yields x = L(49) = 3.278 approximately.
Looking for the W button on my calculator…
t^t is a continuous, differentiable and monotonically increasing function . Since 3^3 = 27 < 256 < 4^4, therefore 3 < t < 4. Therefore, apply Newton's method to get t = 3.278031523596059366055947260535156966261673645376747543163853771604845412696293875445828810498337202... (100+ places of decimal accuracy with near zero effort). No weird / less-known or one-off or unusual (including Lambert) function required to solve this entire class of problems to any arbitrary desired accuracy. [ How would you calculate Lambert W function anyway ? ]
Lambert W Function The Lambert W function, also known as the Omega function, is a mathematical function used to solve equations in which the variable appears both inside and outside of an exponential function or logarithm. Definition The Lambert W function is defined as the inverse function of: f(W) = We^W
t lnt = ln 49 Lnt= 49/t Plot graph, get intersection, simple Ans t= 3.278 -althaf Calicut
Honestly they should explicitly tell about Lambert W function, using it is quite random, and unless student specifically knows it he'll likely invent some other function(like V=lnW) to solve the equation
t^t = 49 t.ln(t) = ln(49) t = ln(49)/ ln(t) since 3^3 = 27 and 4^4 = 256, so 3<t<4 use 3 as initial guess. use any numerical method like fixed point iteration method, Nr method etc. to do this with fixed point iteration method save 3 as ans in calculator. type, ln(49)/ln(ans) and repeatedly spam '=' , you will get 3.278..
@Universee_201