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Triangle of Power

3Blue1Brown·
5 min read

Based on 3Blue1Brown's video on YouTube. If you like this content, support the original creators by watching, liking and subscribing to their content.

TL;DR

Current notation treats exponentiation, roots, and logarithms as separate syntactic worlds even when they express the same underlying relationship.

Briefing

Math notation usually matters less than the underlying visual relationships it tries to represent—but notation becomes a real educational bottleneck when it forces students to learn the same idea three different ways. A single relationship like 2 cubed = 8 can be written as 2^3 = 8, ∛8 = 2, or log base 2 of 8 = 3. In today’s conventions, those forms don’t look like siblings; they behave like separate “languages,” each with its own rules and memorization burden. That mismatch makes logarithms feel especially confusing at first, and it turns what should be one coherent mental picture into multiple disconnected facts.

A proposed fix reframes the three operations using one symmetric diagram: the “triangle of power.” For 2^3 = 8, place 2 in the lower left, 3 at the top, and 8 in the lower right. Then define each operation by removing a corner: to express 2 cubed, remove the bottom-right corner (the missing value is 8); to express log base 2 of 8, remove the top number (the missing value is 3, answering “2 to the what power equals 8”); to express the cube root of 8, remove the bottom-left corner (the missing value is 2). The key idea is that the whole symbol always represents the missing corner’s value, making exponentiation, logarithms, and radicals share the same structural logic.

That symmetry pays off when inverse operations are compared. In standard notation, there are six common inverse-style expressions that students often memorize as unrelated items, with no clear pattern linking them. The triangle of power instead makes those operations follow one consistent scheme, reducing both error rates and the cognitive load of learning multiple syntaxes for the same underlying relationship. The payoff isn’t just efficiency; it also matches how human brains latch onto patterns and build “smooth mental images,” which can keep students engaged long enough to develop intuition.

The triangle also helps unify deeper algebraic identities. For example, the exponent rule a^x · a^y = a^(x+y) corresponds to the logarithm rule log(xy) = log(x) + log(y). In the triangle framework, the top expression and the lower expression become two views of the same missing-corner logic: multiplying quantities associated with the bottom-right corner corresponds to adding quantities associated with the top. The diagram can even suggest how to draw internal annotations—when one corner stays fixed, the remaining corners “like” to add or multiply depending on the operation.

When a different corner is held constant, the pattern can require introducing a new operation. The transcript names it O+, defined by A O+ B = 1/(1/A + 1/B), and notes that this harmonic-mean-style operation appears naturally in physics, such as parallel resistance. The broader claim is that many relationships involving exponents, logarithms, and radicals become more discoverable when notation mirrors the true asymmetries of the underlying equation a^b = c, rather than inventing artificial asymmetries through symbols and words.

The recommendation is practical: try using the triangle of power in notes, and—especially for teachers—introduce it so students can reason from the structure itself. The ideal learning path still starts with “why,” but better notation can make the first “why” questions easier to ask and easier to connect to the math’s essence.

Cornell Notes

The triangle of power is a symmetric notation that unifies exponentiation, logarithms, and radicals. Place 2 in the lower left, 3 at the top, and 8 in the lower right; then each operation is defined by removing a corner, with the whole symbol representing the missing value. This design reduces the need to memorize separate inverse forms that currently look unrelated, making patterns easier to see and mistakes less likely. It also clarifies how exponent and logarithm identities correspond (like a^x·a^y = a^(x+y) matching log(xy) = log(x)+log(y)). With the triangle, holding different corners constant reveals consistent “add vs multiply” behavior and even motivates an operation like O+ that matches physics examples such as parallel resistance.

Why does the transcript criticize current notation for 2^3 = 8, ∛8 = 2, and log_2(8) = 3?

All three statements express the same relationship—“2 to the third power equals 8”—but standard notation makes them look and feel like different concepts. Students must learn separate syntaxes and rules: superscripts for powers, radicals for roots, and log notation (with a base) for logarithms. That forces repeated memorization and increases the chance of treating each form as a separate “language,” which slows learning and makes the math feel fragmented.

How does the triangle of power encode exponentiation, logarithms, and roots?

It uses a triangle with three numbers: lower left, top, and lower right. For 2^3 = 8, put 2 (lower left), 3 (top), and 8 (lower right). To represent 2 cubed, remove the lower-right corner; the symbol’s value is what belongs there (8). To represent log base 2 of 8, remove the top corner; the missing value is 3. To represent the cube root of 8, remove the lower-left corner; the missing value is 2. The same “missing-corner” rule drives all three operations.

What problem does the triangle of power solve regarding inverse operations?

In conventional notation, there are about six common inverse-style expressions that students often memorize as separate entities, with little visible pattern connecting them. The triangle imposes a single structural pattern across these inverses. Because the operations correspond to removing different corners, students can track how each form relates to the others without learning six disconnected rules.

How does the triangle of power connect exponent rules to logarithm rules?

It highlights that both identities reflect the same structural relationship. The exponent rule a^x · a^y = a^(x+y) corresponds to log(xy) = log(x) + log(y). In triangle terms, multiplying quantities associated with the bottom-right corner corresponds to adding quantities associated with the top corner. The diagram makes the shared “missing-corner” logic easier to visualize.

What does the transcript mean by introducing O+ when a different corner stays constant?

When the top corner is held constant, the triangle suggests multiplication in both bottom corners because exponents and radicals turn multiplication into multiplication. The transcript then asks what happens if the lower-right corner stays constant, and answers that an analogous rule requires a new operation: O+, defined as A O+ B = 1/(1/A + 1/B). It notes this operation appears in physics, specifically in computing parallel resistance.

What learning principle does the transcript insist on even while promoting better notation?

The triangle should not replace reasoning. Students still need to ask why the relationships are true and why the pattern changes when different corners are fixed. The claim is that notation should reflect the math’s real structure so that the natural “why” questions students ask align with the underlying numerical facts, not with arbitrary symbol quirks.

Review Questions

  1. How does removing different corners in the triangle of power change which operation you’re representing?
  2. Explain, using the triangle’s logic, why a^x·a^y = a^(x+y) corresponds to log(xy) = log(x)+log(y).
  3. What is the definition of O+, and what physics context is given as an example of where it naturally arises?

Key Points

  1. 1

    Current notation treats exponentiation, roots, and logarithms as separate syntactic worlds even when they express the same underlying relationship.

  2. 2

    The triangle of power places the three numbers (base, exponent, result) in fixed corners and defines each operation by which corner is removed.

  3. 3

    Because the whole symbol always represents the missing corner’s value, the three operations become structurally symmetric and easier to relate.

  4. 4

    The approach reduces memorization of multiple inverse forms by making their relationships follow one consistent pattern.

  5. 5

    Holding different corners constant reveals consistent “add vs multiply” behavior and can motivate new operations like O+.

  6. 6

    O+ is defined as A O+ B = 1/(1/A + 1/B) and is linked to parallel resistance in physics.

  7. 7

    Better notation should accelerate reasoning, not replace it; students should still re-derive and ask why the rules hold.

Highlights

A single equation like 2^3 = 8 can be written three ways, but standard notation makes them feel unrelated; the triangle of power makes them share one symmetric structure.
Each operation corresponds to removing a different corner of the triangle, with the missing value always being what the symbol represents.
The triangle turns exponent and logarithm identities into the same “missing-corner” logic, making log(xy) = log(x)+log(y) feel like the same rule as a^x·a^y = a^(x+y).
When the lower-right corner is fixed, the transcript’s O+ operation (harmonic-mean style) emerges, with a physics example in parallel resistance.

Topics

  • Notation Reform
  • Exponentiation
  • Logarithms
  • Radicals
  • Triangle of Power

Mentioned

  • Sal Khan