## Plotting sine and cosine with matplotlib and Python

In this post we will create a plot using matplotlib and Python. The plot will show two trig functions, sine and cosine on the same set of axes.

## Python Data Types

Python has many useful built in data types. Python variables can store different types of data and can be created dynamically, without first defining a data type. It's useful for engineers to understand a couple of Python's core data types in order to write well constructed code. Below we will discuss a few different data types.

## Unit conversions with Python and Pint

Units and unit conversions are BIG in engineering. Engineers solve the world's problems in teams. Any problem that is solved has to have a context that it is solved in. How heavy can a rocket be and still make it off the ground? What thickness body panels should be used to keep occupants save during a crash? In engineering, a number without a unit is like a fish without water. It just flops around hopelessly without context and is useless. How can we get help using units? Programming is one way. In this post, we are going to use Python and Pint, a python package used for unit conversions, to do a couple of sample unit conversion problems.

## Bar charts with error bars using Python and matplotlib

Bar charts with error bars are useful in engineering to show the confidence or precision in a set of measurements or calculated values. Bar charts without error bars give the illusion that a measured or calculated value is known to high precision or high confidence. In this post, we will build a bar plot using Python and matplotlib. The plot will show the coefficient of thermal expansion (CTE) of three different materials based on a small data set. Then we'll add error bars to this chart based on the standard deviation of the data.

## Unicode characters for engineers in Python

Unicode characters are very useful for engineers. A couple commonly used symbols in engineers include Omega and Delta. We can print these in python using unicode characters. From the Python interpreter we can type:

>>> print('Omega: \u03A9')
Omega: Ω
>>> print('Delta: \u0394')
Delta: Δ
>>> print('sigma: \u03C3')
sigma: σ
>>> print …