### Archives

### Categories

- Art (21)
- Bigger reality (59)
- Blender (21)
- DIY (140)
- GNU/Linux (86)
- Health (30)
- Motorcycle (28)
- Permaculture (121)
- Photography (115)
- Python (20)
- Reprap 3D Printer (101)
- Science and technologies (115)
- Uncategorized (38)

### Website

- Doctor Yourself Health Homesteading website that promotes self reliance.
- Exploring Electric Universe
- F* THE BANK$ This website is run by a feisty group of Occupy Wall Street activists and members of the The Other 98%…
- NASASCAM site 20 years of exposing NASA lies and deceit.
- Professor Ph. M. Kanarev's Books and Lectures Professor Kanarev has developed a new theory of a Microcosm and Mechanodynamics that open up Free Energy technologies.
- PSRAST Physicians and Scientists for Responsible Application of Science and Technology
- Wade Frazier's personal website Free Energy technologies, alternative medicine, abundance paradigm
- Ways of the Wild Institute Wilderness Survival, Wilderness Living, Spirituality, Healing and Awareness

- 3D modeling 3D printer 2006 Yamaha R1 art bird birds Blender 2.69 Buckminster Fuller Bulbul Junior Calculus calibration Canon EOS 1000D Canon Rebel XS cat convert corrupted system Debian GNU/Linux Debian Wheezy Devuan Digital Camera Digital photography DIY dog Earthbag ED AF NIKKOR 300mm 1:4 electronics ffmpeg flowers Free Energy Free Energy technology geodesic dome GIMP GNU/Linux GoPro HD Hero2 health helmet house project Hydraulic press ImageMagick mathematics Mini Kossel motorcycle Natural Farming nature Neal Hirsig Nikon D200 OpenSCAD open source Permaculture photography Physics PLA plant python reprap Reprap 3D Printer Rice science sculpture SmaTrig Sony A6000 Steel Fisher steel pipe SymPy technology time lapse truth Wheezy wildlife wood working Xorg 기술 두차 쌀 자연농사

# Tag Archives: mathematics

## Converting rotation matrices of left-handed coordinate system

In left-handed coordinate system, positive angle is clockwise direction. In right-handed coordinate system, positive angle is anti-clockwise direction. I spent many hours to find out how to convert rotation matrices of left-handed coordinate system. The solution is to replace the … Continue reading

## A differential equation on Kahn academy

I began to study Differential equations lately. It has been relentless days. Tools I use: Paper and digital text books Pencil and printing papers Scientific calculator CAS (Computer Algebra System) – Sympy and ipython notebook Knowing Kahn academy site was … Continue reading

Posted in Science and technologies
Tagged Calculus, differential equations, Kahn academy, mathematics
Leave a comment

## sympy – find equations for the lines that are tagent and normal to the curve at (1, 2).

Chapter 2 Practice Exercises, p183

Posted in Python
Tagged Calculus, mathematics, normal line, python, SymPy, tangent line
Leave a comment

## sympy – sawtooth function

Calculus and Analytic Geometry, George B. Thomas and Ross L. Finney Exercises 2.5 81, p163 s = 0.78540 – 0.63662*cos(2*t) – 0.07074*cos(6*t) – 0.02546*cos(10*t) – \ 0.01299*cos(14*t) plot(s, (t, -pi, pi)) dsdt = 1.27324*sin(2*t) + 0.42444*sin(6*t) + 0.2546*sin(10*t) + 0.18186*sin(14*t) … Continue reading

Posted in Python, Science and technologies
Tagged Calculus, cos(x), derivative, mathematics, python, sawtooth function, sin(x), step function, SymPy
Leave a comment

## sympy – appling the chain rule manually to find derivative of a function.

I spent few hours to figure out how to apply the chain rule manually to find derivative of a function due to poor documentation of SymPy. I’m not that smart guy.

## sympy example – finding tangent lines to a function

Chapter 2: Derivatives Exercises 2.2, p130 43. Find the tangents to Newton’s Serpentine (graphed here) at the origin and the point (1, 2). 47. a) Find an equation for the line that is tangent to the curve at point (-1, … Continue reading

Posted in Python, Science and technologies
Tagged Calculus, mathematics, python, SymPy, tangent slope
Leave a comment

## sympy – continuity test of functions

All functions I used here from Chapter 1 Exercises on Calculus and Analytic Geometry (9th Edition) by George B. Thomas, Ross L. Finney. It has discontinuity at 2 of x. Smooth graph of a function means it has continuity in … Continue reading

Posted in Python, Science and technologies
Tagged Calculus, limit, mathematics, python, symbolic, symbolic computation, SymPy
Leave a comment