# Welcome to Basic.
Some collection of written notes on some basic mathematics.
Currently teaching:
- [[calculus/index-math-8-spring-2025|Math 8 Calculus 2.]]
- [[basic-ordinary-differential-equations/index-math-15-spring-2025|Math 15 Ordinary differential equations.]]
Some other notes, in-progress updates (slow):
- [[basic-ordinary-differential-equations/index-math-15|Math 15 Ordinary differential equations notes.]] (Only material after midterm 1 so far).
- [[beginner-number-theory/0|Beginner number theory.]] _in-progress_
- [[basic-real-analysis/0-index-basic-real-analysis|Basic real analysis.]] _in-progress_
- [[basic-linear-algebra/0-index-basic-linear-algebra|Basic linear algebra.]] _in-progress_
- [[matrix-linear-algebra/0-index|Math 13 Notes and additional comments.]] _in-progress_
&[320,390,0 demo](https://dev.bonsoon.net/quilt/)
@image[300,300]
setBorder(10);
initPicture(-3, 3, -3, 3);
axes(1, 1, "labels", 1);
stroke = "#ddd";
strokewidth = "1";
// Loop through the grid to draw slope segments
for (var i = -3; i <= 3; i += 0.4) {
for (var j = -3; j <= 3; j += 0.4) {
var x = i;
var y = j;
// x' = y, y' = x
var dx = y;
var dy = -x;
// Calculate length to normalize the vectors
var len = Math.sqrt(dx * dx + dy * dy);
if (len > 0) {
// Normalize and scale the segment length (0.15 is the half-length)
var scale = 0.1 / len;
var xStart = x - dx * scale;
var yStart = y - dy * scale;
var xEnd = x + dx * scale;
var yEnd = y + dy * scale;
stroke = "blue";
line([xStart, yStart], [xEnd, yEnd]);
}
}
}
text([1.5, 2.8], "dx/dt = y");
text([1.5, 2.5], "dy/dt = -x");
@endimage
