There's a lot of stuff in here. Join our community! You can get a nice tour in the Getting Started section and also by viewing Navigating Math Tools by Bethany Hudnutt.
Using only elementary geometry, determine angle x. Provide a step-by-step proof.
You may only use elementary geometry, such as the fact that the angles of a triangle add up to 180 degrees and the basic congruent triangle rules (side-angle-side, etc.). You may not use more advanced trigonomery, such as the law of sines, the law of cosines, etc. There is a review of elementary geometry below.
Use SAGE for studying a huge range of mathematics, including algebra, calculus, elementary to very advanced number theory, cryptography, numerical computation, commutative algebra, group theory, combinatorics, graph theory, and exact linear algebra.
Research shows that the difference between what is taught and what is learned is often greater than most instructors realize. Lillian McDermott from the University of Washington discusses current and future trends in math and science education.
Number Theory, Combinatorics, Geometry, Algebra, Calculus, etc...
Now you can instantly draw the golden sections, or other divine proportions, as an aid to composition. This plugin can draw fibonacci sequences such as the golden sections, golden spiral and the golden triangles. In addition it also can draw the harmonious triangles and the rule of thirds - based on composition through identity. The best way to use the plugin is to output the drawing to a transparent top layer you can move around for cropping.
This is fairly hilarious to math geeks. It assigns a piano key with a value and plays "pi" to 1,000 places. It's quite beautiful ; )
The math computer scientists use regularly, in real life, has very little overlap with the list above. For one thing, most of the math you learn in grade school and high school is continuous: that is, math on the real numbers. For computer scientists, 95% or more of the interesting math is discrete: i.e., math on the integers.
Math is the language of symbols. The way we work with numbers tells us a lot about their relationships, patterns, and the ways they change. Math helps us describe both similarities and differences and also helps us think and solve practical problems.