# Are calculus and real analysis the same thing?

1. I guess this may seem stupid, but how calculus and real analysis are different from and related to each other?

I tend to think they are the same because all I know is that the objects of both are real-valued functions defined on $\mathbb{R}^n$, and their topics are continuity, differentiation and integration of such functions. Isn't it?

2. But there is also $\lambda$-calculus, about which I honestly don't quite know. Does it belong to calculus? If not, why is it called *-calculus?
3. I have heard at the undergraduate course level, some people mentioned the topics in linear algebra as calculus. Is that correct?

Thanks and regards!

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λ-calculus is something completely different: see en.wikipedia.org/wiki/Lambda_calculus –  lhf Apr 12 '11 at 1:45
I would say "calculus is to analysis as arithmetic is to number theory", including real and complex analysis under that umbrella. –  Alex Becker Apr 12 '11 at 1:47
The term "calculus" can be used generally to mean something like "manipulation". The subject in math that we call calculus today was previously more well known by a longer name "calculus of infinitesimals", so named because at the time of its development, it was thought of as exactly that, the science of manipulating infinitesimally small numbers. It's in this sense that $\lambda$-calculus is named: it deals with the manipulation of "lambdas". See: en.wikipedia.org/wiki/Calculus_%28disambiguation%29 –  matt Apr 12 '11 at 1:49
I think "calculus" in general means "to calculate". So, with this in mind, calculus uses the results of analysis to calculate things. Analysis is all the theory behind calculus. –  Matt Gregory Apr 12 '11 at 2:00
@matt: thanks! I have heard that at the undergraduate course level, some people refer to topics in linear algebra as calculus. Is that correct? –  Tim Apr 12 '11 at 2:05
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## 1 Answer

1. A first approximation is that real analysis is the rigorous version of calculus. You might think about the distinction as follows: engineers use calculus, but pure mathematicians use real analysis. The term "real analysis" also includes topics not of interest to engineers but of interest to pure mathematicians.

2. As is mentioned in the comments, this refers to a different meaning of the word "calculus," which simply means "a method of calculation."

3. This is imprecise. Linear algebra is essential to the study of multivariable calculus, but I wouldn't call it a calculus topic in and of itself. People who say this probably mean that it is a calculus-level topic.

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we had courses analysis 1 and analysis 2 but the books had titles like Calculus. However these books were total 2000 pages too complex that any textbook for calculus i seen seemed childish too simple . So now i understand ,that books are analysis books. –  Parhs Mar 3 '12 at 2:15
@Parhs: What books? –  Tim Mar 3 '12 at 2:28
They are written in greek. I was wrong , the total pages are 2800 (2 theory and some problems and examples and 2 other only problems.) It uses literature from apostol,ayoub,birkhoff,comtet,ciang and lots of other[80 total].But they are extreemly hard to read. Even the most difficult textbook for calculus is easy compared to them.And they are given at engineering school –  Parhs Mar 3 '12 at 2:54
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