# weird

1. ### I am getting a weird message on the top of my screen

syntax error, unexpected T_STRING in /home/math/domains/mathhelpforum.com/public_html/includes/class_core.php(4715) : eval()'d code on line Thats what it says on the top of every forum page on this site.... why does this happen and I cant seem to see any latex expressions evaluated. What should...
2. ### 'Weird' Factorial Series

Hello, I am given the series\sum_{n=1}^{\infty} \frac{1\cdot3\cdot5\cdot...\cdot(2n-1)}{2\cdot5\cdot8\cdot...\cdot(3n-1)} and I am asked to determine whether it converges or diverges. The problem is that I can't come up with equation representing the series above, to me it looks like a modified...
3. ### weird inequalities problem with reciprocals on both sides (inequalities)

This is question number 9 of James Stewart Mathematics for Precalculus 6th Edition I already know the method where you substitute every single value from S into the equation but I was wondering if there was just a way to simplify it
4. ### Weird problem

Here is the problem I find not comprehensible. Let a, n be non-negative integers, let A be the set of positive consecutive integers with • min(A) ≤ a • |A| ≤ n (a) write down a formal definition for the set B which contains all such sets. (b) How many functions f : A → {0, ..., r} are there...
5. ### Weird limit concept extension

Okay, so I'm laying in bed all night unable to sleep. And I start getting a weird idea, which makes me laugh. But as I'm in my stupor pondering the matter I concluded that there's enough there to be worth a post to check. So. Limits. \lim_{x \to \infty}. Which infinity? Hear me out. I...
6. ### Matlab weird help

]As you can see in the photo, I have the values for A1..A7 and B1..B7. Then, I plot a graph for the upper side A1..A7 and fit an exponential to it in Matlab. The eq is y=22.297e^-5.323x After, I plot the graph for the lower side B1..B7 and fit an exponential to it. The eq is y=40.949e^-5.002x...
7. ### A weird Derivative

I'm trying to find the first and second derivative (at 0) of a rather strange function. Let g(x) = 1 if x is rational, -1 if x is irrational. Let f(x) = x^3* g(x). I convinced myself earlier that the first and second derivative at 0 does not exist as the function is not continuous, but i'm not...
8. ### Weird Equation

cos2x + 2sin^2x -3 = -2 cos^2x - sin ^2x +2sin^2x = 1 cos^2x + sin^2x = 1 1=1 I "solved" it but my answer is weird, has no variable. I believe this is an identity rather that an equation. However how would I answer this question? The back of the book says and I do not understand that...
9. ### A Really Weird Metric Space

So, I've been asked to prove this. I've no idea where to start, would like to see what this problem is actually talking about. First, let v be a metric v : \mathbb{R}\times\mathbb{R} \to \mathbb{R} defined by v(x,y) = Min(1, |x - y|) We have shown in class that this generates the usual...
10. ### A weird limit involving e and 1/n

Hi, I'm working on a problem but stuck at a weird looking limit: \lim _{n \rightarrow \infty } [1- e^{-a-log(n)}]^2 It is suppose to converge to e^{-e^{-a}} but: I wrote the limit as \lim _{n \rightarrow \infty } [1- \frac {1}{n}- \frac {1}{e^a}]^n and as =\lim _{n \rightarrow...
11. ### Weird algebra

(x+1)/(x-2)=3/(x-2)+5 - Wolfram|Alpha Why on earth can't I just multiply by (t-2) and get the solution t=2 ?! To make it absolutely clear that I should be able to just multiply by (t-2), I can rewrite this equation as: \frac{t+1}{t-2}=\frac{5t-7}{t-2} I am VERY confused.. I do realize that...
12. ### weird hexagons and green thm

Hi, I would appreciate if someone could help. thanks. Calculate the work done by the non conservattive force F=x³j in moving a particle,around the regular hexagon with vertices at (√3,1),(0,2),(-√3,1),(-√3,-1),(0,-2) and (√3,-1) in that order. (use greens theorem). For this question I tried...

http://i49.tinypic.com/r9r1w8.jpg <--- story problems are here with diagrams I'm not sure how to approach this, I guess I just don't remember the concepts Please explain to me how to do this :(

15. ### Weird problem with my problem

\frac{sinx+1}{sinx+1} if I call (sinx+1)=a then we have \frac{a}{a}=1 however when I split the original problem up I get \frac{sinx}{sinx}+\frac{1}{1}=2 I know I am just doing something silly but what is it?
16. ### Weird calculus/geometry question

Hi, I'm a senior in calculus. I know this thread list is supposed to be for university students, but there's no calculus listed in the high school section. My tutor referred me to this site because we couldn't solve this before the session ended. The problem actually sounds like a geometry...
17. ### Weird trig triangle question, can't work through

Solve for theta, the big triangle is an isosceles. I've tried working it through by applying sine rule to the two separate partitions but can't get anywhere with the giant mess of an equation i get. I've got it to simplify to this. , where u=θ/2 but can't get any further. I know θ should equal...
18. ### How to integrate this weird function.

Hello, how would you integrate this: I was stumped when I saw this question, as I couldn't use a substituition to solve this. If somebody knows how to integrate this, could they please show me how they go about doing so? Thanks :)
19. ### A weird situation in calculus (product rule)?

So how many times have you tried doing (fg)' and instead of doing fg' + f'g you directly did f'g'? Im just wondering if this situation ever really exists? For what functions is (fg)' = f'g' Thanks.
20. ### How to express 69 in weird way ?

69= \int\limits_{10}^{13} 2x\, dx 69=\binom{12}{2}+\binom{3}{2} 69=\displaystyle \lim_{x \to 5}\left(\sum_{k=0}^2 (4-k)\cdot x^k\right) 69=\frac{1}{4} \cdot \displaystyle \sum_{n=0}^2 2^{2^{n+1}} Be creative !!