Other
Georgia Tech: The Four Color Theorem
An explanation and proof of the Four Color Map Theorem. Includes illustrative images and a plethora of information.
Wolfram Research
Wolfram Mathworld: Theorem
This simple MathWorld site defines theorems and briefly explains how a theorem is produced.
Paul Dawkins
Paul's Online Notes: Calculus I: Proof of Various Integral Properties
The tutorial examines proofs of several properties of integrals. Topics discussed are the fundamental theorem of calculus, extreme value theorem, work, and mean value theorem. Class notes, proofs, and examples with detailed solutions are...
Texas Instruments
Texas Instruments: Proof of the Pythagorean Theorem Using Transformations
In this activity, students will explore visual proofs of the Pythagorean Theorem using area and transformations. They will use the Cabri Jr. app to perform translations on the squares constructed on the two legs and the hypotenuse of a...
Lawrence Hall of Science
The Math Page: Skill in Algebra: The Pythagorean Theorem
Here is a site that clearly and thoroughly explains the Pythagorean Theorem from solving for missing sides of a right triangle through its proof. There are example problems solved, problems for the student to attempt, and answers to the...
National Council of Teachers of Mathematics
The Math Forum: Nctm: Ask Dr. Math: Binomial Theorem by Induction
Question-and-answer page about a proof of the Binomial Theorem by induction.
Math Is Fun
Math Is Fun: Pythagoras' Theorem
This resource investigates the Pythagorean Theorem. Includes animations, examples, proofs, and links to problems and activities.
Cut the Knot
Cut the Knot!: Analogues and Generalization of the Pythagorean Theorem
This site discusses the theorems and other findings which are directly related to the fundamental Pythagorean theorem. Be sure to click on the link to information on Pythagorean theorem to find several proofs of the theorem.
Oswego City School District
Regents Exam Prep Center: Triangle Inequality Theorems
This tutorial discusses triangle inequality and provides practice problems for students to try out their skills. The teacher resource page contains a lesson plan for a yummy activity involving licorice.
Other
Mathematical the Four Color Theorem and Computer Proof
This site describes the role of computer involvement in the four color map theorem.
Cut the Knot
Cut the Knot!: Napoleon's Theorem
This site gives an explanation of Napolean's Theorem and gives several links to Napoleon's Theorem.
Khan Academy
Khan Academy: Line and Angle Proofs
Explore different ways of proving some theorems about lines and angles. Some transformations are used. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video, or receive hints.
Cut the Knot
Cut the Knot!: Monge's Theorem of Three Circles and Common Tangents
Very good site presenting a Trig problem dealing with tangents lines and circles, then linking the student to the solution
Khan Academy
Khan Academy: Proofs With Transformations
Explore different ways of proving some theorems about lines and angles. Some transformations are used.
Mathematics Archives
Math Archives: Visual Calculus: Quotient Rule
This site gives the quotient theorem and examples that the student can work through.
Alabama Learning Exchange
Alex: Geometrica Fights Back!
This activity is designed to give students practice with the properties of special quadrilaterals (parallelograms, rectangles, rhombuses, squares, trapezoids, and kites). The students are provided with a "murder mystery" sheet with...
Wolfram Research
Wolfram Math World: Divergence Theorem
This site gives proof of the Divergence Theorem. Students should be somewhat familiar with divergence and gradient to utilize this site.
Massachusetts Institute of Technology
Mit: World Math Web: The Squeeze Theorem
This page contains an explanation and a proof of the squeeze theorem.
Other
Xah Lee: Some Theorems on Rotation and Translation
This site is for the purpose of using proofs for geometry. It helps by giving some useful theorems.
Paul Dawkins
Paul's Online Notes: Calculus I: Proof of Trig Limits
The tutorial investigates the squeeze theorem. Class notes, definitions, and examples with detailed solutions are included. The class notes are available in pdf format.
Mathigon
Mathigon: Graphs and Networks: Map Colouring
This lesson focuses on map coloring and the problem of proving that 4 colors would work for all maps. Francis Guthrie had to color a map of counties in England. He observed that four colors seemed to suffice for any map he tried, but he...
Alabama Learning Exchange
Alex: The Pythagorean Theorem in the Real World
The introduction of this lesson plan has students verifying the famous Pythagorean Theorem with a hands-on proof. Students will then apply the Theorem in one of two ways: by solving for the side lengths of a right triangle and by...
Mathematics Archives
Math Archives: Visual Calculus: Antiderivatives/average Value of a Function
This site has the definition of average of a function by using integrals. The site also contains the proof of the mean value theorem which may be viewed one step at a time. There are links to related exercises whose answer is shown one...
Stanford University
Stanford Encyclopedia of Philosophy: Frege's Logic
Lengthy and detailed, but also quite technical, article explaining the major theorems of Frege's logic. Introduction gives a helpful overview and bibliography is included at end, but anyone without a background in logical notation may...