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[Daily puzzle] No calculator math
812 sats \ 20 comments \ @south_korea_ln 12 Oct 2024 science
Solve this without using a calculator. Several ways are possible... Show your logic, don't just write out the final number for this one.
999^2-998^2=?
This shouldn't be too difficult.
Previous iteration: #719143
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221 sats \ 0 replies \ @SimpleStacker 12 Oct 2024
999^2 - 998^2 = \int_{998}^{999} 2x dx
That's the area of a trapezoid with width 1 and heights 2 * 998 and 2 * 999, which is 1997
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221 sats \ 2 replies \ @Undisciplined 12 Oct 2024
(998 + 1)(998 + 1) - 998^2 = 2*998 + 1 = 1997
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43 sats \ 1 reply \ @south_korea_ln OP 12 Oct 2024
And yet another way.
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0 sats \ 0 replies \ @Undisciplined 12 Oct 2024
I was fortunate that no one took mine.
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221 sats \ 1 reply \ @Scroogey 12 Oct 2024
(1000-1)^2 - (1000-2)^2 = 1000^2 - 2000 + 1 - 1000^2 + 4000 - 4 = 2000 - 3 = 1997
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1 sat \ 0 replies \ @south_korea_ln OP 12 Oct 2024
That's also one of the ways.
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200 sats \ 1 reply \ @jakoyoh629 12 Oct 2024
(999+998)(999-998)=1997*1=1997
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25 sats \ 0 replies \ @south_korea_ln OP 12 Oct 2024
That's indeed one of the ways.
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1 sat \ 11 replies \ @ChrisS 12 Oct 2024
How do I learn more about how to do the math symbols in markup? Is there a way to see the raw markup on posts?
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1 sat \ 9 replies \ @south_korea_ln OP 12 Oct 2024
It's not really markup, it's MathJax.
Mathjax supports different syntaxes: MathML, TeX, and ASCIImath.
I use TeX. There are plenty of tutorials on how to write equations in TeX.
$$
a^3 + \sqrt{3} + \frac{1}{a+\hbar}+\int_{i=1}^a \exp{(iax)} dx < \infty
$$
for instance will yield
a^3 + \sqrt{3} + \frac{1}{a+\hbar}+\int_{i=1}^a \exp{(iax)} dx < \infty
I did not test MathML and ASCIImath here yet.
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0 sats \ 8 replies \ @Scroogey 12 Oct 2024
deleted by author
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22 sats \ 6 replies \ @SimpleStacker 12 Oct 2024
Single dollar signs work in latex but not in mathjax. Probably because single dollar sign is too common in regular html
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1 sat \ 5 replies \ @south_korea_ln OP 12 Oct 2024
Oh really? I think I already used it too.
Let's try. $\sqrt{2}$ (single dollar, inline) and double dollar (block equation):
\sqrt{2}
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1 sat \ 4 replies \ @SimpleStacker 13 Oct 2024
Oh, hmm. The implementation I use in my website doesn't allow single dollar signs.
It's actually probably better that way, since I've seen dollar signs mess up other peoples' posts here.
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1 sat \ 0 replies \ @025738dda8 12 Oct 2024
In TeX, single $ means "change to math typesetting mode" (treat it as"inline" math). The double $$ is similar, just it typesets it as a separate block of math/figure (it adds alignment, spacing, etc.).
I'd expect similar behaviour.
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0 sats \ 0 replies \ @Scroogey 12 Oct 2024
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