1 files changed, 43 insertions, 0 deletions
diff --git a/site/content/math/index.typ b/site/content/math/index.typ
new file mode 100644
index 0000000..a1a6c4a
--- /dev/null
+++ b/site/content/math/index.typ
@@ -0,0 +1,43 @@
+#import "/common.typ": post, link-self
+
+#show: post.with(
+    title: "Math notes",
+)
+
+This part of the site is a loose collection of my math notes.
+
+- #link-self("math/angle_between_two_vectors")[Angle between two vectors]
+- #link-self("math/atan2")[atan2]
+- #link-self("math/integrating_sin2x")[Integrating sin² x]
+- #link-self("math/integrating_cos2x")[Integrating cos² x]
+- #link-self("math/ray_vs_sphere")[Ray vs. sphere intersection]
+- #link-self("math/rotational_symmetries_bravais_lattice")[Possible rotational symmetries in a Bravais lattice]
+
+= Notation
+
+Since there are so many conventions in linear algebra, I've decided to pick one and be consistent. Below is what I use throughout the site.
+
+== Vectors
+
+#table(
+    columns: 2,
+    [$bold(x)$], [A vector (bold font).],
+    [$x$], [The norm of the vector $bold(x)$ (a scalar), if it appears in the text. Otherwise, it's some scalar.],
+    [$x^2$], [The inner product of a vector with itself (a scalar). Equivalently, the norm of the vector squared.],
+    [$|bold(a) + bold(b) times bold(c)|$], [The norm of a vector expression (a scalar).],
+    [$bold(a) dot bold(b)$], [The inner product of two vectors (a scalar).],
+    [$bold(a) times bold(b)$], [The cross product of two vectors (a vector).],
+)
+
+== Matrices
+
+#table(
+    columns: 2,
+    [$hat(M)$], [A matrix.],
+    [$hat(A) hat(B)$], [A matrix product (a matrix). The former is *premultiplying* the latter or, equivalently, the latter is *postmultiplying* the former.],
+    [$hat(M) bold(x)$], [A matrix premultiplying a vector or, equivalently, operating on it (a vector).],
+    [$hat(A) times.circle hat(B)$], [The Kronecker product of two matrices (a matrix).],
+    [$hat(M)^(-1)$], [The inverse of an invertible square matrix (a matrix).],
+    [$op("det") hat(M)$], [The determinant of a square matrix (a scalar).],
+    [$op("Tr") hat(M)$], [The trace of a square matrix (a scalar).],
+)