#Found this in a Linear Algebra textbook, wondering if it's correct?

38 messages · Page 1 of 1 (latest)

lethal pasture
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I graphed the two points on 3D Desmos, and it doesn't show to intersect at (1,1,1). Nor does the two surfaces touches (1,1,1). Is this textbook wrong?

The textbook is Fundamentals of Linear Algebra by James B. Carrell.

found-this-in-a-linear-algebra-textbook-wondering-if-its-v0-nso6lpy1zfhe1.png
analog scaffoldBOT
#
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acoustic solar
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It might mean (1, 1, 2). A typo.

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Wait, but then that wouldn't be true either.

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But you can see from the equations that (1, 1, 1) isn't a point on either suface.

barren prism
acoustic solar
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If you change the second surface to "z=.." you could use (1, 1, 2) as an example.

acoustic solar
barren prism
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oh shit you're right, it's not z^2

lethal pasture
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Yea... should I just abandon this textbook

acoustic solar
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What book?

barren prism
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which book is it?

lethal pasture
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Fundamentals of Linear Algebra by James B. Carrell

barren prism
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name doesn't ring a bell, lemme check

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title page look like this?

image.png
lethal pasture
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Yep

barren prism
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alright what page

lethal pasture
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Page 16

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yea I only just started using it, and I was like yeah this is wrong

barren prism
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well, the argument is correct provided solutions exist

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just need to replace the 1,1,1 with a proper solution

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im not really a fan of the structure of the notes tho

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you're better off working with some other linear algebra text

lethal pasture
barren prism
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I swear by Gilbert Strang

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there's also Axler "Linear algebra done right"

lethal pasture
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This one?

barren prism
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bingo

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there's also lots of problems and further exposition

lethal pasture
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For context, I'm self learning linear algebra after my undergraduate because I didn't pay attention in maths (due to online during covid).

barren prism
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Strang's LA is highly praised

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can't go wrong with it

lethal pasture
merry vesselBOT
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@lethal pasture

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