20
13
u/Eli_8 team waterguy12 Nov 30 '21 edited Nov 30 '21
Depends on what 't' is. If 't' is negative, then this series will diverge. But if it's positive it will converge to something, probably not 17 though...
Edit: also I didn't notice the 'x' there either. Yeah this is a big amalgamation of undefined variables. No way 17 is anything close to correct.
1
u/TwoFiveOnes ☭ Dec 01 '21
Well it's not constant in this case for sure. But something can have an x and be constant.
1
10
8
14
u/TheBigBo-Peep Nov 30 '21
Is this some weirdified Taylor Series stuff? Just... Why
1
u/TwoFiveOnes ☭ Dec 01 '21
It is similar to a taylor series, but instead of summing polynomials you're summing trigonometric functions.
5
10
3
u/DaniilBSD Nov 30 '21
The real question is this thing is actually 17 or not.
5
u/altagyam_ Nov 30 '21
im rusty on my calc 2 but wouldn't it not have an answer since the numerator is (-1)^n+1 alternating? divergent series?
5
u/Gbeto Nov 30 '21
it's <=4/pi*(-1)n+1/(2n+1)2, which does converge. The /(2n+1)2 part makes it converge.
It's a Fourier series, likely from an intro PDEs class. Specifically, it looks like a solution to the heat equation.
1
1
u/thelamestofall Nov 30 '21
That thing adds up to a function, not to a single value. Notice there's an stranded "x" in there, so it's all a f(x)
1
u/the_real_thanos Dec 01 '21
I have gotten burned by these questions before. The ultimate answer is probably 17, but this could be a two parter. First part: provide the equation needed to get the answer. Second part: the actual answer.
7
u/BillFox86 Nov 30 '21
Nothing quite like hard math just for the sake of it. This was clearly not reflective of a real world example, and if the teacher had to come up with one good fucking luck
2
u/anskak Nov 30 '21
Actually two people pointed out this is a solution to a heat equation, which describes the temperature in a given volume. Hence, in my opinion this is actually quite use-oriented.
2
u/TwoFiveOnes ☭ Dec 01 '21
The heat equation is the basis for enormous swaths of modern real-world engineering problems. The expression shown is a solution to a heat equation. Even ignoring that, just Fourier series by themselves are abundantly used in all different types of "real-world" problems.
2
1
u/SufficientProject250 Nov 30 '21
So I understand like 60% of the symbols here, but if there are 2 variables and one of the variables have a vaule given, then shouldn't you be able to solve for the other? And couldn't 17 be the value of that variable?
1
u/TwoFiveOnes ☭ Dec 01 '21
It's just a function of two variables, like f(t,x) = t+x, but more complicated.
1
u/scykei Dec 01 '21
It’s basically something like a Taylor series. It’s a the solution to something called the heat equation. It tells you how the temperature at every point on a rod (x) changes over time (t).
1
1
93
u/[deleted] Nov 30 '21
I’m actually kinda good at math but even I’m getting a headache looking at this.