# What is integration?

1. Sep 16, 2006

### mathman100

ok, so in one of my lectures our prof. showed us a graph, (that pretty much looked like an upside down parabola.) We had to find the area under the curve, and she told us we had to use integration. I'd never even heard of it before, and I don't understand what all the symbols mean, or how to use them. Can anyone help me out?

2. Sep 16, 2006

### G01

You need to learn some calculus, start frequenting the math forum. In a very modest, brief definition, integration is the process of adding infinitely small pieces togther to make a whole.(NOT THE MATHMATICALLY RIGOROUS DEFINITION FOR SURE!!!!) Integration can be used to find the area under a curve.

3. Sep 16, 2006

What class is it for? That's really odd that a teacher would be like, "use integration to find the area under the graph" when you've never done it before.

Unless she was going to be explaining what integration was? that would make more sense.

You should ask her what integration is. Everyone else in the class is probably where you are at.

4. Sep 16, 2006

### Data

http://en.wikipedia.org/wiki/Integral

What do you know? Have you learned differential calculus (how to find derivatives, etc.)? Did you miss any lectures in which integration may have been explained? Do you have all the prerequisites for this course (and are you sure you're in the right course?!)?

Essentially, there are two branches to calculus, integral calculus and differential calculus. Differential calculus deals with differentiation, and integral calculus deals with antidifferentiation.

You also undoubtedly have a textbook assigned for this course. In addition to asking your instructor to explain things, you should probably take a look at it! It'll undoubtedly explain integration, though it's very strange that you're in a course where your instructor assumes knowledge of integral calculus and you've never heard of it before (especially if, as I'd guess, this is a first-year university course? They should know what you're expected to have learned already!).

Last edited: Sep 16, 2006
5. Sep 17, 2006

### Plastic Photon

6. Sep 17, 2006

### gnomedt

Or multiplication, because it's repeated addition and turns distance into area, area into volume, etc.

7. Sep 19, 2006

### Robokapp

basically it's opposite of derivation. in slang it'd be defined as "kicking an equation up to the next level"

it's like getting distance traveled if you know speed...or getting speed if you know acceleration. Or getting area if you know perimeter...or volume if you know area.

in plain math, it's finding area between the x-axis and the curve you're looking at over a closed interval...and it's the opposite operation than derivation. Yes it's the super-steroids version of an addition in a way.

the symbols are pretty simple if you look at them 1 by 1.

$$\int$$ is just the symbol of operation. the lower and upper numbers tell you between what values of x you do this operation...and the dy/dx or dx...just is, and does nothing but make the operation possible (it's easier to put it that way even if some smart people will trow rotten tomatoes at me for saying that).

8. Sep 24, 2006

### Stu091

It's basically the limit as a summation approaches a number right?

9. Sep 25, 2006

### Sojourner01

Yep, summation of an infinite number of infinitely thin polygons whose length is defined by the value of the function at that point.

10. Sep 25, 2006

### J77

To the OP: if it's a new course, and you haven't heard of integration, I'd be worried what other prerequisites you don't know about...