The ambiguous case in SSA
How the height test decides whether one angle and two sides produce no triangle, one triangle, or two triangles.
Guides
These essays are meant to be read before or after you run the matching calculator. They do not replace a textbook chapter. They explain the decisions the tools make.
What a complex number means in this calculator
What a + bi stands for when a quadratic discriminant is negative, and what the page does not claim.
Domain of a logarithm
Why the argument of a real logarithm must be greater than 0, and how a horizontal shift moves that cut-off.
Which triangle formula should I use?
How to choose Pythagoras, the law of sines, or the law of cosines from the parts you already know.