UNI_FOUNDATION · Discrete mathematics · DISC.RECURRENCE

Recurrences

Recurrences

Practice this skill
Intuition

Understand first, compress later.

Discrete mathematics studies countable structures, combinations, graphs and recursion.

Switch representations
Tree diagramP(R) = 0.6, P(B) = 0.4
0.60.40.60.40.60.4SRBRR
RB
BR
BB
R = red marbleB = blue marbleedge probability
Two draws with replacement: every edge carries the probability of that step. Along a path you multiply (0.6 · 0.4 = 0.24), across the four paths you add — and the four leaves total 1, as they must.
Formal view

You can recurrences when you can recognise the underlying objects, select valid rules and check each step for equivalence or logical implication.

Why does it work?

This skill sits on a prerequisite network. If a step is unstable, repair the missing prerequisite instead of merely doing more items of the same type.