Mathematics

Hello could you please explain me with easy words how do you find out the domain and range of a function, for example f(x) =(x+5)^3+2 how would you know the domain and range of that function? thank you

hello I'm asked to write the equation y= 2x^2-4x+6 in the form y= a(x-h)^2 this is what i have been doing first I divide by 2 x^2-2x+3 then I try to complete the square (x^2-2x+1)+3 (x+1)^2 now i don't know what else to do Should I multiply that one times 2 because I divided by two and then add it to 3 to get 5? and so the answer would be (x+1)^2+5 But I know that's wrong because I graphed both equations and they aren't the same graph please help me.

Could you find all positive integer solutions to ... x^y - y^x = x + y

The theory that I am attempting to formulate is being complicated by the intrusion of ancient Greeks into the mix. Their number system is decimal in nature (probably lacking zero). My question is this. How old would a decimal Greek number system be likely to be? Could it be older for instance than the Arabic Islamic system which, by definition, must be newer than 500AD I always believed that the Muslims invented the decimal system. A date would be useful. :-) :-) -------------------------------------

So I have the equation y=x^2 - 2x-5 I graphicaly determine the zeros to be 3.45 and -1.45...shouldent I be able to substitute these values in for x and solve the equation...which should be zero. 3.45 gives and answer near zero 0.0025 (perhaps rounding error) but -1.45 is nowhere close. What's the deal? Nic

Hi all. Now i got confused; this site: http://www.mathopenref.com/subtend.html shows the subtended angle for the sun being 32 arc minutes or 0.52 degree. That seems very small. Does it mean that in a 12.0 hour day, the sun path could be drawn as 346 sun disks fitting edge to edge on the sky ? Am trying to create a formula, chart or nomograph to calculate the needed diameter of a distant mirror reflecting the entire sun disk. (As a heliostat of what diameter positioned at a given distance will show the complete sun disk) Miguel

is the answer 20 days?? sorry for such posts!! i am preparing for few exams and these questions are killing me because i make very silly mistakes in Maths. kindly bear with me!!

This is awesome: http://en.wikipedia.org/wiki/Proof_that_0.999..._equals_1

I thought it was nice, even though if he started multiplying figures with numbers like 6 or 8 it would be pretty tedious Math Lesson: A new way to multiply

Hi, I am having trouble with this question Assume that a blood vessel, such as a vein or an artery, has the shape of a cylindrical tube with radious R and lenght L. because of the friction at the walls of the tube, the velocity, v, of blood flowing throught the blood vessel is greatest along the central axis of the tube and decreses as the distance r from the axis increses unitl v becomes 0 at the wall. the relationship between v and r is givin by the law of laminar flow, discovered by the French physician Poiseuille in 1840. the law V= p / 4nl (R^2 - r^2) where n is the velosity of the blood and P is the pressure difference between the ends of the tube. If P …

Hi, can someone help me with this question? Three resistors, R1, R2 and R3, are connected in parallel in an electrical circuit. The total resistance, R, in ohms is given by: 1/R = 1/R1 + 1/R2 + 1/ R3 R, R2, and R3 are increasing at rates of 0.1, 0.5 and 0.7 ohms/s, respectively. Determine the rate at which R1 is changing when R = 50 ohms, R2 = 70 ohms, and R3 = 60 ohms. Find R1 1/50 = 1/R1 + 1/70 + 1/ 60 (1/50)-(1/70)-(1/60)=1/R1 How do you solve something that is in the deominator? the i just Plug eerything in to the equation d/dt 1/R = d/dt 1/R1 + d/dt 1/R2 + d/dt 1/ R3 right?

First off I am not the greatest math student but I have been having an argument with a person I know who is convinced the earth is 6000 years old lol. He doesnt believe carbon dating to be true but then I brough up Pangea and he agreed that alot of geological evidence shows Pangea was fact. Well the math problem is how would I calculate the time it would take for continental drift to bring the plates to where they are today? I would need to know the following: speed of continental drift, approx position of Pangea landmass and the current place of landmass. I am 100% sure it accounts for well over 1 billion years or more but I dont know how to figure it out prope…

This is a problem similar to one is Stewert's Early Trancendentals: A boat is being pulled towards a dock by a rope. The rope is reeled in at a constant speed. What is the speed of the boat moving across the top of the water when it is a certain distance away from the dock? (x and y are perpendicular) The solution is fairly straight-forward: Use the relationship between the distances [math]r^2 = x^2 + y^2[/math] Differentiate in time: [math]2r \frac{dr}{dt} = 2x\frac{dx}{dt}[/math] Here, dr/dt is the speed of the rope (constant) and dx/dt is the speed of the boat. I will now call these vr and vb. Finally: [math] v_b = v_r\frac{r}{x}[/math] This is the solutio…

Hi, I was wondering where you can find resources and tips on contest math and similar problem solving type questions. I really want to develop my reasoning and problem solving skills. Thanks a bunch.

hello im new her this is only my second post so i dont know if i put this in the correct place or not but yeah... my problem is that on a test today my teaches asked us to factor: 2(x)squared+13(x)+15 i factored it out and got (2x+10)(x+1.5) my reasoning is as follows 2(x squared+6.5x+7.5) i divided by 2 2(x+5)(x+1.5) factored the terms (2x+10)(x+1.5) if you F.O.I.L. out the terms you get the original equasion (which i thought was "factoring" but however my teacher got a different answer) after thinking over this for a while i came to the conclusion that the term "factor" should have been replaced with "find the simplest factor" because what i had was a facto…

is the answer 64??

I've been doing exercises that require simplifying expressions since forever, but I don't think I ever questioned what it actually meant. The reason I ask was that I came across this expression: [math](\frac{x+y}{y+z})^{2}(y^{2}-z^{2})[/math] And tried to simplify it, I got to [math](x^{2} + y^{2} + \frac{2xy}{y+z})(y-z)[/math] and then thought, hey, is that actually any simpler?

Is there anyway to solve an equation (without logarithms) such as: [math] 2^x=x^2 [/math] and [math] 2^x=x^3 [/math] where x is in the exponent and the base of two different terms? If so, how?

Can anybody give that answer for this please :: Circular bylinder of R=6cm is concentric witht the Z-axis btw z=-3cm & 3cm find the volume.

Hi, I need help with this question is this right? Thanks

For odd reason, the Latex in this forum doesn't show up to me. It shows up as an image with "x" as "not displayed." I can still read the code if I put my mouse over it but I'm not sure what happened. Is there something in my setting that I have to do or..?

I recently heard of a different kind of implicit differentiation, apparently it works like this: [math]\frac{dy}{dx} = - \frac{dt}{dx} \div \frac{dt}{dy}[/math] Where t is a made-up variable. This makes complete sense to me except for the negative sign. Why is there a negative sign and what is the name of this method?

Actually, is there any way how to find the lograthm of a number WITHOUR USING THE LOG TABLES ITSELF?? Is it possible? Please give a detailed explanation and steps to do that.

Hi all, would anyone be able to give me a little bit of help with this question. for part (a) i did this.... our sphere is given by [math] x^2 + y^2 +z^2 = 25 [/math] putting in z = 3 to find out part of the sphere gives: [math] x^2 + y^2 = 16 [/math] so we change to the parametric representation of the part of the sphere we are interested in sphere which is [math]\vec{r}(\theta,\psi) = (4sin\psi cos\theta) \vec{i} + (4sin\psi sin\theta) \vec{j} +(4cos\psi) \vec{k} [/math] then [math]\vec{r_\theta}(\theta,\psi) = (-4sin\psi sin\theta) \vec{i} + (4sin\psi cos\theta) \vec{j}[/math] [math]\vec{r_\psi}(\theta,\psi) = (4cos\psi cos\…

Not sure if this belongs in the Physics or Math forum. I'm leaning towards Math more. Say, when scientists do experiments, record data, and come up wtih a formula, how do they prove that the formula is correct? I'm talking about those formulae that cannot be mathematically derived. One example might by Hooke's Law.There will inevitably be some error so how do they prove, besides just looking at the graph, that the formula should still stand in spite of the errors affecting the data? I know that they can't prove that the formulae is 100% true, but they can show, using statistical analysis that the formula is highly unlikely to be untrue. My question is, HOW? Say I'…