some corrections needed

[gregbo]

I noticed a few items need correction, such as:

• A function is decreasing whenever a < b, f(a) > f(b)

• Power to a power: (x^{n})^{m} = x^{nm}

• Law of excluded middle: P(x) + P(¬x) = 1

[kathgironpe]

Thanks I took an academic break. This was started 4 years ago. I will have documentation for contributors.

[kathgironpe]

The notes are generally correct. I will add the graph to make it clear.

[kathgironpe]

This graph looks like right. The notes on functions are correct but lack context.

[kathgironpe]

Notes are better with images, but I didn't like the dark background of the images. I could start converting colors later.