Section One Flashcards
What was MATH in the EGYPTIAN ERA?
Hash-mark system
Numbers and measure, empirical uses
Reciprocals
The odd formula for pyramids, area, volume.
What was MATH in the BABYLONIAN ERA?
More advanced hash-mark system!
Numbers and measure still, empirical uses
Chunks of base 60, no fractions
Astronomy! Use in timekeeping and angle measurements.
PYTHAGORAS vs THALES. What what??
Discrete vs continuous! Pythagoras believed the universe was discrete, Thales believed the universe was continuous.
One argument against discrete was the study of commensurable numbers. Could you express the side and the diagonal of a square as the ratio between two whole numbers?
How many PRIME NUMBERS are there?
INFINITE. PROOF: Let Ep be all the prime factors of p multiplied, then + 1. Even though the result isn’t prime, it decomposes into smaller primes that were LARGER than the largest prime factor in Ep
Can you FIND PRIME NUMBERS?
There are several attempts. Mersenne primes, Fermat’s attempt,
What’s the difference between POTENTIALLY INFINITE and COMPLETED INFINITE?
“Potentially” means it can theoretically go on forever, but it hasn’t yet. Like time! Or primes.
“Completed” means it’s sitting there right now, staring back at you. Like all the rational numbers between 0 and 1!
ONTOLOGY vs EPISTEMOLOGY. What what??
Ontology: What is math?
Epistemology: How do we know math is math is works?
BABYLONIAN CLAY TABLET??
I dun understand this but it’s early on in the notes
MORE about ONTOLOGY.
PLATO and ARISTOTLE.
PLATO believed that mathematical objects existed in a higher dimension, casting their shadows onto our cave-world.
ARISTOTLE believed mathematical objects are only abstractions (A for Aristot-al Abstractionista!). That we take the idea of a straight stick, and subtract wood and width till we get the line.
MORE about EPISTEMOLOGY.
Math is governed by logical deduction, but everyone agreed that we all had to start with some unprovable truths.
EUCLID built the Elements of Mathematics with five axioms (he needed a sixth though. the cheater.) and went on to prove everything mathy from the ground up.
ELEMENTS OF MATHEMATICS. What were the five axioms?
Segments, circles, angles.
1) A line can be constructed from two points.
2) This segment can be extended indefinitely.
3) A circle can be constructed from a radius r
4) All right angles are the same.
5) Parallel Postulate/ Playfair’s axiom
(6): Lines don’t have holes, and can intersect each other.
CONIC SECTIONS! What do you know?
Ellipses: PF1 + PF2 = 2r
Parabola: PF = PD
Hyperbola: PF1 - PF2 = constant
Eccentricity: PF/PD = e, where e is the eccentricity
GREEK CONTEMPORARIES: PAPPUS
PAPPUS: Conic sections work! Found the directrix of an ellipse.
GREEK CONTEMPORARIES: ARCHIMEDES
290-212 BC: Did geometric calculus before the invention of calculus! Also did volume and surface area work. Also wrote the Sand Reckoner, what a tragedy.
GREEK CONTEMPORARIES: EUDOXUS
400BC: Similar triangles, proportions, LIMIT IDEA!! (method of exhaustion). Approximating a circle by inscribing polygons of increasing size.