kramer2011 said:
All these clever replies and not one specific example of how, during the course of say, a mechanical engineers day, what problems he would be trying to solve using a method of integration...?
I'm currently learning all about these methods, and knowing to what practical purpose they are applied will help me greatly in understanding the values I arrive at. For example, when you find the area under a curve, what does it represent?
There seems to be come clever people on here, now be smart.
What people are asking is for the poster of the thread to be smarter. He/she could find many examples in textbooks specific to the field of interest -- or even state the specific area of interest in the thread... note the TYPE of engineering was not even posted in the original thread, let alone a specific topic within the field -- that's why I was leaving this thread alone (perhaps hoping the original poster came back with more specification).
Granted, maybe prior responders could be more polite (and some have been) but now you've butted in (withyour first post to a "real" part of PF I might add) criticizing the whole... and your post isn't really even smart. You ask about a mechanical engineer, but what is he/she in the process of designing... is the main interest of his design -- vibration, distortion under weight, or one of many types of "fluid flow" -- be it heat flow, air flow (over a wing), or water flow (over a ship's hull, through a pipe, or perhaps even groundwater flow regarding a contaminant) etc.? All these things can be either directly solved by integration (for simple systems), or some type of numerical integration (for complex systems). Note: I'm not even a mechanical engineer, but these are the things you'll often see in an introductory "boundary values" text.
Then you ask about the area under a curve... The area under a curve (or for that matter its slope) can represent many things, or nothing of any real physical significance or interest at all, depending on what is plotted in the curve.
To be polite, however, to the original poster and others of interest in this topic: Some areas in the past where I've done numerical integration: The first time I did numerical integration was when I was a student in a chemistry class and needed to do numerical integration to analyze some data regarding pH in a titration (forgive me that this was 15 yrs ago -- I don't have the book anymore and don't recall the details because I don't work in chemistry or chemical engineering). More recently: when I worked in the field of electro-optical engineering and wanted to design optical waveguides for certain systems, and I did some numerical analysis to estimate the power (intensity) profile of the exiting beam (this depends on Maxwell's equations, boundary conditions required within these equations, and the specific boundary profile in space created by the waveguide and the material it was made of -- I mention this because some other respondents mentioned Maxwell's equations). There was also some analysis of how the time profile of a "square pulse" would be changed as it propagated through the structure (to see if it spread too much to be above a certain signal to noise requirement -- with given types of noise being added).
As an aside, numerical integration is also important in other fields (like biology -- say for population analysis or kinematic studies of cell processes, etc.) or economics, but again, those are not my particular fields.