studiot

With election fever upon us here is an interesting proposed derivation of the word Parliament. Scroll down to the end of the article. http://www.bbc.co.uk/news/magazine-32273170

This belongs in homework. I will make a small adjustment to DrP's post Integration by parts is for a product of two functions u(x) and v(x) but not directly multiplied, since one is a differential. [math]\int udv = uv - \int vdu[/math] You need to chose the u as the function that can most easily be differentiated and the dv as the function that can most easily be integrated. (sometimes there is little to chose between) So in this case chose u = x and dv = sin2x Can you take it from here, you should have three terms in your answer

Is this coursework? In which case it belongs in homework help. What happens if you take the log of both sides of your equation and then differentiate each side?

I would starty by explaining my question in a bit more detail. What you said may be OK in a classroom when you are in the middle of discussing the subject and have lots of context, but i am not sure what you are asking. Are you talking about steady running and load on the machine or accelerating a load from a standing start? Both the power and efficiency are affected by the compression available in the cylinder, if the slider is a piston. The speed of running and the mass of the piston will also be involved. Or are you just asking how to maximise efficiency - ie reduce friction etc?

I don't know what the flow rates are for a hyperbaric chamber.

Well my calculator made it 16.3 mins - say 15 mins for safety. A 5L tank at 50 bar expands to 5x50 = 250 L at 1 bar. Leave 5L in the tank as spyman said makes 245L available. Using this at 15L/min is 245/15 = 16.333 mins.

For the benefit of the OP and others, instead of squabbling further with john cuthber, here is a physics 102 exam paper extract, with answers. This shows, amongst other things, a wave that is both amplitude and frequency modulated. http://www.physics.umd.edu/courses/Phys102/brill/EX2-2.HTM

Sorry, I wouldn't know I've never been on a social media site, I not sure i would even know how. However you are correct in that this is based on something I read in our local what's-on rag, 'Suited and Booted', with my own take on some of the items and some additions of my own. However the subject has clearly put put up for wide discussion in the public domain, which is what we are doing.

Please stop all this holier than thou stuff and look at the pics, courtesy g3npf. The top one is AM the bottom one is FM If you look carefully you can see visually what I am saying. The frequency of the AM carrier is fixed and does not vary. The frequency of the FM carrier varies continuously from (fc-fd) to (fc+fd). Every cycle of the FM carrier has a different period. End of.

Go at it folks. It depends on your definition of 'green'.

Are you asking because you actually want to find out the correct answer. Since you clearly misunderstand frequency modulation I will try once more. In frequency modulation the carrier frequency is varied in accordance with the amplitude of the modulating wave. The maximum is known as the deviation frequency fd

Checking out at the supermarket recently the young cashier suggested I should bring my own bags because plastic bags were not good for the environment. I apologised and explained, “We didn’t have these things back in my earlier days.” The cashier responded “That’s our problem today. Your generation did not care enough to save our environment for future generations.” Back then we returned milk pop and beer bottles to be washed, sterilised and refilled. We walked to the local shops and didn’t climb into a car every time we had to go two minutes up the road. Back then we washed babies’ nappies because we didn’t have the throwaway kind. We dried them on a clothes line, not an energy gobbling machine so wind and solar power really did dry our clothes. Kids got hand-me-down clothes from relatives, not always new designer labelled stuff. Back then we had one TV or radio in the house, not one in every room. In the kitchen we stirred and blended by hand rather than having electric machines for everything. When we posted a fragile item we used screwed up old newspaper as packaging, not plastic foam or bubblewrap. Back then we didn’t burn petrol to cut the lawn. We used a push mower that ran on human power. We exercised by walking and working so we didn’t need to go to a health club to run on exercise machine run by electricity. We drank from a fountain instead of purchasing plastic bottles of water. We refilled ink in writing pens and replaced blades in razors. Back then we took the bus and kids rode their bikes or walked to school. A stag night meant a few mates going on a pub crawl, not two dozen people flying to Prague. Back then we didn’t need a computer to receive a signal beamed from a satellite 2,000 miles out in space just to show a photo of a meal we had just prepared to a friend who lives next door. But, of course we weren’t green back then.

No not really, but your are claiming they are the same so why do we have two terms? While you are at it perhaps you would like to resolve the following. In an AM signal the carrier frequency does not alter. It is constant. In an FM signal the carrier frequency is constantly varying. The deviation from the carrier centre frequency is proportional to the modulating signal amplitude. In an AM signal there is no modulation information in the carrier. In fact it is possible to remove the carrier entirely and some forms of AM do exactly this. In an FM signal all the modulation information is contained in the carier. Removal of the carrier will result in total loss of the information. A clear difference there.

I didn't say anything of the sort. The broadcast signal has an instantaneously unique frequency and amplitude. It is one signal. It is not several signals. The best way I can explain this is to consider a cyclist. At some particular instant he is cycling North East at 14 mph. Now mathematically we can resolve his velocity into 10 mph North and 10 mph East. But there is still only one cyclist, not two travelling on two different directions. At another instant he may be travelling at a different velocity with differents components in the north and east directions. In the same way the broadcast signal is one signal that may be mathematically resolved into components, not in space but in time or frequency. There are more and different and resolutions possible for these generalised coordinates.

The purpose of mathematical notation is to facilitate the making and communicating of statements in mathematics. It serves no other purpose and blindly attempting to redefine it simply obstructs that purpose. As that is all you have achieved so far you cannot lay claim to any such argument since you have yet to commence one. This is a complete waste of everyone's time.

Like I said, calling tha AM sidebands FM is not strictly accurate. The amount of modulation is a recoverable function (preferably one of simple proportionality) to the modulating signal. This is not the case with AM sidebands. Look at the maths.

That is not strictly accurate, as shown by my simple mathematical description in post#17

What branch of engineering? Even the best doesn't do them all.

Are you qualifying your statement about the xi s? If they are specific numbers then of course all the differential coefficients are zero, as they are for any constant. But that is introducing new material, not before stated. It is a pretty pedestrian statement that 0 + 0 + 0 + 0 +........................ = Well suprise, 0 Originally, you stated an identity concerning a bunch of variables, labelled xi This may be true for some values of xi but not for others, nevertheless it could be a valid equation. To qualify for an identity it must be true for all values of all the xi s This is elementary.

Of course there is another alternative. For the frequency modulating signal to itself be AM modulated. This is, of course, what happens in practice insofar as an audio signal continuously changes in both frequency and amplitude.

I think modern military frequency hopping radio uses an entirely different form of modulation, but if they were to use AM for the signal, frequency hopping could count as a form of combined modulation. The combination maths works like this (simplified to show the principle) Consider a carrier wave y = A cos (wct + B) y is the instantaneous total signal, which is a function of time. A = amplitude Where wc = angular frequency = 2pifc of carrier t = time In a simple unmodulated wave, A and B are constants In AM we make A variable without affecting B and In FM we make B variable without affecting A So if we introduce a second signal frequency ws = 2pifs as a second variable Ccos (wst) and C is another constant. Then we can substitute this for either A or B to obtain an AM or FM signal respectively. AM is then {Ccos (wst)} * {cos (wct + B)} FM then A cos { wct + Ccos (wst) } A combined AM~FM signal would be {Ccos (wst)} * { cos[wct + Ccos (wst)] } Now substituting either A or B is enough to convey all the carried information so why would you want to complicate matters by substituting both? Why would you be wanting to modulate with two separate modulating signals? There are other, easier ways to do this. One example of the TV signal has already been given. Another example would be the radio code data which uses a sideband. Further the limitations on the amplitude and frequency of the substituting are different and a double substitution would have to satisfy the limitations of both simultaneously.

Since this obviously interests you perhaps you would like to know that Newton's law of heat transfer states for you mixing circumstances that The rate of heat transfer is directly proportional to the temperature difference and independent of the quantity of heat. Can you make anything of that?

Why don't you try it and see? But be careful you don't scald yourself

You mean a super European DisUnion? ( OMG )10

So that's how the camel passed through the eye of the needle.