Mistake Master
Student view — seeing the site as a student does
Mistake Master · AP Precalculus · Unit 2 · Step-Through Animation

The Log Is the Exponential in a Mirror

You'll learnto see the logarithm as the exponential reflected across the line y = x.

Draw y = 2ˣ. Fold the plane along the diagonal y = x. The curve that lands on the other side is log₂x — same points, coordinates swapped. Every fact about the log falls out of that one fold: its domain, its wall at x = 0, its refusal to level off. Watch the fold happen, and watch the reciprocal impostor 1/2ˣ fail the audition.

9 STEPS · 6 QUICK CHECKS · y = 2ˣ  ⇄  y = log2x · v2

y = 2ˣ ⇄ log₂x
Before you start
What you're looking at
The curve y = 2^x and the diagonal y = x, with a point like (3, 8) about to become (8, 3).
The question
What happens to each point's coordinates when the plane folds along the diagonal?
Watch for
Coordinates swapping, the equal axis scaling that makes the fold land on the curve, and the reciprocal 1/2^x failing to match.
Step 1 / 9