Math, Better Explained: Learn to Unlock Your Math Intuition
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Read between December 3 - December 19, 2019
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Defining 00 as 1 makes many theorems work smoothly. In reality, 00 depends on the scenario (continuous or discrete) and is under debate. The microwave analogy isn’t about rigor: it helps us see why 00 = 1 can be reasonable, in a way that “repeated counting” does not.)
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0^0 = 1
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Growth curves written like 2x are from the observer’s viewpoint, not the grower.
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To get into the grower’s viewpoint, we use the magical number e. There’s much more to say, but we can convert any “observer-focused” formula like 2x into a “grower-focused” one: 2x = (eln(2))x = eln(2)x
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every exponential curve is just a scaled version of ex: ax = (eln(a))x = eln(a)x Every exponent is a variation of e, just like every number is a scaled version of 1.
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Euler’s formula looks utterly baffling: eix = cos(x) + isin(x) This means eiπ = cos(π) + isin(π) = –1 + i(0) = –1 which is so surreal I need to write it again: eiπ = –1
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Euler's formula
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Euler’s formula describes two ways to move around a circle.
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Euler’s formula says that eix is the same process as moving around a circle using (cos(x) + isin(x)).
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imaginary growth rate should give you “interest” in the imaginary direction and it would start pulling you 90-degrees!
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On the contrary, real growth pulls you straight
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Imaginary growth: When I grow, don’t push me forward or back in the direction I’m already going. Rotate me instead.
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Imaginary growth
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After 1 second you’ll be at 90 degrees (i), at two seconds 180 degrees (i2 = –1), and so on.
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If your growth rate is a larger imaginary number (2i), you can consider the growth happening for twice as long (remember how e merges rate and time?). But it’s still pushing you in a perpendicular direction, which doesn’t change your speed.
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Spinning faster doesn't make sense
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if your growth rate is complex (a+bi) then the real part (a) grows or shrinks your magnitude like a normal exponent does, while the imaginary part (bi) rotates you. But Euler’s formula (as written) is about purely imaginary growth (eix).
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Circular motion: Change continuously by rotating at 90-degree angle (imaginary growth rate).
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Circular motion
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we should expect ii to make things smaller. And it does: ii = e ~ .2.
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i^i
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