Mathematical Proofs Galore

I have written quite a number of articles on mathematical proofs, so I want to summarize them in this post.  Most of these proofs are high school level, so students who are mathematically inclined are encouraged to read them.

Proof Basics 

• Introduction to Mathematical Proofs
• Proof Tutorial 2: Proving the Irrationality of Square Root of 2 by  Contradiction
• More examples of Proof by Contradiction
• Proof by Contradiction: Knights and Liars

Geometry

• Angle Sum of Polygons
• Why is the angle sum of the interior angles of a triangle equal to 180 degrees?
• A US President’s Proof of the Pythagorean Theorem
• Using Similarity to Prove the Pythagorean Theorem
• The Algebraic and Geometric Proofs of Pythagorean Theorem

Trigonometry

• The Proof of the Tangent Half-Angle Formula
• An Elementary Proof of the Cosine Law

Number Theory

• Proof of the Sum of Square Numbers
• A Simple Proof of the Arithmetic Mean Geometric Mean Inequality
• Another Proof of the Sum of the First n Positive Integers
• Prime Series 3: Proof of the Infinitude of Primes
• Proof that log 2 is irrational

Calculus

• An extensive explanation about the  definition of limits
• Limit by  proof: Example 1

I will update this list every time I have written proof-related posts, so you may want to book mark this post.