## [Index] Calculus in a Single Variable

1. Differential Calculus in a Single Variable
1. Definition of Derivatives using big O notation
2. Line Tangent to a Curve
3. Exponential Function
4. Tangent Lines as Linear Approximations
5. Some Useful Trigonometric Limits
6. Differentiating Trigonometric Functions
7. Inverse Function Theorem
8. The Natural Logarithm, the inverse function to the exponential mapping.
9. Optimization: its motivation, the First Derivative Test, an example optimizing a rectangle’s area
10. Implicit Differentiation
11. Curve Sketching
12. Applications
13. Techniques
2. Integral Calculus in a Single Variable
1. The Antiderivative part 1, part 2
2. Finite Series
3. Riemann Summation a first step towards definite integration
4. Example Riemann Sum working with $f(x)=x^{2}+1$
5. Fundamental Theorem of Calculus
6. Properties of the Integral
7. Not all functions are (Riemann) integrable!
8. The Natural Logarithm Revisited!
9. Integration Techniques:
10. Applications of Integrals
1. Calculating Arc-Length of Curves
2. Calculating the Area for a Surface of Revolution (Part 1) when we revolve about the $x$ axis
11. Optimization
1. Calculus isn’t useless: When Velociraptors Attack, calculus solving matters of life and death!
12. Thinking “Infinitesimally”

## Blog/Life Update

Just to keep readers in the loop: I have not forsaken you! I just have a job now…

I got hired to program in Clojure, a peculiar member of the Java family and distant relation to the LISP clan.

Nevertheless, I am still writing mathematical notes, and will try to post them when time allows. Do not expect them to be as regular as they used to be!

I am going to finish up vector calculus, beginning with line integrals. After vector calculus, linear algebra will commence!

## Introduction to Double Integration

1. Consider ${z=f(x,y)}$. What is the volume of the region
(1)$\displaystyle S = \{ (x,y,z)\in{\mathbb R}^{3}\mid z=f(x,y),\; a\leq x\leq b,\; c\leq y\leq d\}$
The first thing we do: consider the rectangle ${R=[a,b]\times[c,d]}$ and form a partition of ${[a,b]}$ into ${M-1}$ segments and ${[c,d]}$ into ${N-1}$ segments. This gives us a mesh of rectangles ${R_{ij} = [x_{i-1},x_{i}]\times[y_{j-1},y_{j}]}$ as specified by the following diagram:

Observe the area of ${R_{ij}}$ is
(2)$\displaystyle \Delta A = \Delta x\Delta y.$
We can approximate the volume ${V}$ of ${S}$ by a sort of Riemann sum, picking points ${(x_{ij}^{*}, y_{ij}^{*})}$ in ${R_{ij}}$ and taking
(3)$\displaystyle \sum^{M}_{i=1}\sum^{N}_{j=1}f(x^{*}_{ij},y^{*}_{ij})\Delta A\approx V.$
However, as with Riemann sums, we recover the exact volume when we take the limits ${M,N\rightarrow\infty}$:
(4)$\displaystyle V = \lim_{M,N\rightarrow\infty}\sum^{M}_{i=1}\sum^{N}_{j=1}f(x^{*}_{ij},y^{*}_{ij})\Delta A$
if the limit exists. Continue reading

## Notes on Mathematical Writing

1. I’m going to be posting my double integral notes, but I’d like to discuss my strategy when writing “more rigorous” mathematics. Modern mathematics consists of definitions, theorems, and proofs…so I’ll discuss the idiosyncrasies of each. (I’ll probably revise this several times…) Continue reading

## Meta: Higgs Boson

So, they discovered the Higgs Boson the other day.

I think I will ultimately get to discussing the Standard Model in mathematical detail. It would be awesome to discuss the classical Standard Model, then the quantum Standard Model.

I have already posted some (updated) Notes on Lie Groups, some notes on Fourier analysis, and some notes on Relativistic Quantum Mechanics.

Not to mention my Notes on Feynman Diagrams, focusing on the φ4 model and QED.

But in the short run (i.e., next couple weeks), I will be discussing:
(a) double and triple integrals,
(b) curls and divergences,
(c) changing coordinates and Jacobians,
(d) line integrals,
(e) Green’s theorem,
(f) Surface integrals,
and much, much more!

## Lagrange Multipliers

1. So, last time we considered finding extrema for some function ${f\colon{\mathbb R}^{n}\rightarrow{\mathbb R}}$, but what if we constrain our focus to some surface ${g\colon{\mathbb R}^{n}\rightarrow{\mathbb R}}$? For example, the unit circle would have
(1)$\displaystyle g(x,y) = x^{2}+y^{2} - 1=0$
How do we find extrema for ${f(x,y)=xy}$ on the unit circle? Continue reading

1. Remember for a curve ${y=f(x)}$, we have maxima and minima occur whenever
(1)$\displaystyle f'(x_{0}) = 0$