We all know that many mathematical formulas are derivatives of other mathematical formulas. By substitution and equating two expressions mathematicians have achieved numerous mathematical formulas. This creates a situation of difficulty for a young maths student. This is particularly the case with trigonometry. In trigonometry, the primary trigonometric functions are sine and cosine. And all the rest is just derivation.
Now if we can draw a tree diagram of trigonometric formulas on a wide page. We will assign the primary branches of the tree diagram to sine and cosine. Then we will derive the ratio identities (reciprocal functions) in the secondary branches. And the most complex formulas will be placed in the tertiary branches.
This will enable a student to understand the roots of every mathematical formula. This will make it easy to remember.