Mathematics

hi all , i can't figure out how i am ment to use the stated fact about tan x. the way i'd do it is dividing the series expansion for cos(x) into that for sin(x)... but yeah i dunno any advice would be greatly appreciated __sarah__

i am new to this forum and not exactly sure if this post belongs here. i need a concrete idea for a determinant. i understand the determinant as the volume of the parallelopiped in the n dimensions corresponding to the order of the determinant. but is there an alternate idea? while working with polygonal numbers and determinants i found that the 3*3 order determinant of any 9 consecutive n-polygonal numbers is -(3*(n-2))^3. i was trying to understand what this result could mean but since my idea of the determinant is vague i was trying to go backwards and understand the determinant. anyway does this result have anysignificance? i proved this by obtaining a general form…

This is the problems on the 46th International Mathematical Olympiad. My friends got excellent result from it, some of them are still very young, the youngest is 2 years smaller than me. That could depress me much. [as I even could not get the qualification to join the competition] http://gifted.hkedcity.net/Gifted/ActReview/imo2005Mexico/pdf/1dayenglish.pdf http://gifted.hkedcity.net/Gifted/ActReview/imo2005Mexico/pdf/2dayenglish.pdf

hey guys could i get a hint at how to do this problem please? i just can't quite work out what my first step should be,.... Thanks -Sarah

Hi all! i can't work out the method to solving this problem or proving it i suppose i guess induction doesnt work but i am stumped for ideas, if anyone has any hints they could give that would be great! i don't to be told exactly how to do it at the moment, but i do need a few hints to get me started. Cheers Sarah

can someone please explain to me how it goes from the first line to the second? (from a normal equation to an infinite series)?? Thanks Sarah

e^(i*pi)+1=0. What is it used for? Why is it special? Ok, it relates pi,e, i, 1, and 0, but does it have a practical application?

hey everyone this is a physics/maths ish question. to do with the michelson-moreley experiment. about light travelling up the arm to the mirror kind of thing anyway, i don't know how to get the approimation part (i gather it is a first order appoximation?) can i do this using linerisation (taylor series stuff) or what? (i don't know how to do binomial expansion at the moment ) Thanks Sarah

hey i have another question if someone is willining to help i can't work out how to use the c and v in this diagram ?? Thanks guys Sarah

What's the convention nowdays? The reference book I am using (which is pretty old btw) goes [math]a_1+\cfrac{b_1}{a_2+\cfrac{b_2}{a_3+\cfrac{b_3}{a_4+\ldots}}}[/math] While the online resources goes a_0,b_1,a_1,b_2... Also which one is more conventional [math][a_1;a_2,a_3][/math] or [math][a_1,a_2,a_3][/math] I know it doesnt matter, but I just wanna stick to the standards.

can someone cleverer than me point out how this problem goes from the second last line to the last? Cheers Sarah

Hi all again! I'm sure there is a simple answer/solution to this problem...or a way to do it anyway, i just can't seem to get it. why does this = 1/e? Thanks Sarah

i have no idea what anything above a 2-sphere would look like. a 2-sphere is like the surface of a ball. a 1-sphere is a circle. a 0-sphere is two points. why is a 0-sphere two points? i would have thought that a 0-sphere would be nothing since it is the set of all points a certain distance from the center in zero dimensions. how do you know which two points the sphere is?

Ok, here is the question (From an old textbook I found...) Princess Amira demands only the most luxurious of accommodations. So for her bath, she had glacial ice from Terror Mountain shipped to her palace in the Lost Desert. There, the ice was carved into a perfect sphere, exactly 2 meters in diameter. The ice sphere melted into her hexagonal bath measuring 1.5 meters on a side, and 0.8 meters deep. If the desert heat uniformly melts the surface of the ice at a rate of 1.5mm of depth per minute, how many minutes will it take for her bath to be completely full? Please round up to the nearest minute, and assume the volume does not change between solid and liquid sta…

Myself and a few friends have been wondering what exactly infinity is, and does it really exist? i, personally, do not believe in infinity. what are your views?

This might be a real simple one, not sure. I want to make a box (let's just say a cube) where 5 of the panels are the same width, and one panel is a different width. I also want to calculate the heat flow into the box which requires knowing the width. What's the best way to do this? I did (5*width A + 1*width B)/6. Is the average width the best method to use? Thanks

Hello. If anyone could help me out and offer any insight, I would be totally grateful! A repeated measures T-test for each group showed one group is signficant and one group is NOT significant. So why would my mixed ANOVA test show NO Group signficance (main effect) and NO Time*Group (interaction effect) signficance? More details: I ran a mixed ANOVA with: Between-groups variable = Group (2 levels) Within-groups variable = Time (2 levels) Time (main effect) is significant Group (main effect) is NOT significant Time*Group (interaction effect) is NOT significant. HOWEVER: 1-way repeated measures ANOVA for Group A, is significant. Paired Samples…

I have worked out the formula for plotting a torus but I cannot seem to simplify it into a general equation. This is what I have got: [math](a-\sqrt{x^2 + y^2})^2 + z^2 = b^2[/math] Where [math]a[/math] is the radius from the origin to the center of the pipe and [math]b[/math] is the radius from the center of the pipe to the surface. Any attempt I make to remove the square root just complicates things even more.

Hello, I found this forum last week while looking for resources to help with my return to college adventure. I am returning to school to finnish my Math Degree after more than 10 years. I droped out of school when my wife was pregnant to find work in the then strong economy. The Dot Com boom was just getting underway at that time and the fruits of my labor were many. However in the down turned economy even after down sizing my families home, vehical, recreation time (no more cable television or movies), my job satisfaction is at an all time low. Realizing that I dont mind living with less I have decided to change careers and become a High school Math Teacher (and h…

Two identical ships next to each other in the middle of a river heading against the current; one at full throttle developing 1000 horsepower just counteracts the current and does not advance at all. The other is anchored. How many horsepower does the anchor produce ?

A person at the centre of a circle needs to tarvel to 5 cities on the circumfarance of the circle. Each city has 5 gates that allow him/her to get through to the city. There is a charge involved when going through each gate. Furthermore, after going through a gate, the charge on all the other gates change (ie they are dynamic). The person is aware of the resulting change in charge by going through a gate, BEFORE entering it. I hope I haven't confused you too much!. I'd like to know your thoughts on this problem. How you would approach a problem like this. A possible matrix???? See it differs from the coonventional TSP problem by the fact that the charges…

Is there a good 3 dimensional (cartesian coordinate system) graphing calculator online anywhere? Again I have tried several times but couldn't find anything free AND good...

Okey, i am confused about this matter. I have two different samples. One is 5 untreated/control samples (same kind) and the other is a 50 treated samples (same kind). I wonder what kind of statistic methods i can use to compare the results between them? I don't think that i can use ANOVA, since they need at least 3 different samples. Besides i can not use T-test or Z-test either, since the former needs both samples to be at a small number n<30, while the latter needs both samples to be large n>30. My samples is n=5 (controll samples) and n=50 (treated samples). Hope for inputs. Thank you!

Hi guys! I'm told arg( z/z-2)=pi/4 How do i find the locus of this? so far i did. but i don't know if this is correct. from argz - argz-2=pi/4 [math]\frac {\frac{y}{x}-\frac {y}{(x-2)}}{1+\frac{y}{x}\frac{y}{x-2}}[/math]=[math]1[/math] then [math]=> (xy-2y-yx)(x-2)=(2x-2)x(x-2)[/math] therefore [math]-2y=2x-2[/math] so y=1-x Thanks in advance

To a bunch of Math people, this question will be pretty easy... But do it completly alebraicly (no graphing). We did this question in high school calculus, but we were able to use a graph. I refused to "cheat" by graphing it, and tried it the algebraic way. It took me several pieces of paper, but I was able to do it, and was very proud of myself, but I was trying to show someone how to do this and I forgot how I did it (I keep comming up with a whole bunch of Ø's and 2?'s that I couldn't get rid of). You have a circle with radius "r." You cut out a sector of the circle at an angle of "Ø." You turn the two circle segments into cones by taking the two lines create…