A positive-definite matrix is an important concept in linear algebra.

There are times when we perform calculations with the haversine in trigonometry.

He drew an equilateral triangle shape.

He is an expert in orthoepy, teaching pronunciation.

He made a model of a regular tetrahedron.

This orthophoto shows the details of the terrain very clearly.

He turned thirty years old.

This picture is fixed to the frame.

This plant needs oxygen to perform photosynthesis.

In this story, Zuan is the protagonist, and his adventure continues.