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# A Small Problem I Made

Can you do this problem in under one minute?

If $$f(x)=(x+1)(x^2+x+1)$$, expand $$f(x)f(-x)$$.

There's a nice trick here that I made

Note by Cody Johnson
2 years, 4 months ago

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Doesn't it turn into $$(x^3+1)(1-x^3)$$ so it's basically just $$1-x^6$$ · 2 years, 4 months ago

What makes you post this, $$\textbf{Mr. TrollKing}$$ ? · 2 years, 4 months ago

I thought it was interesting to pair up the factors in two ways. It seemed interesting to me :) · 2 years, 4 months ago

Yeah great, that is cool.,. · 2 years, 3 months ago

Nice! 1 - x^6 is that correct? Don't know if I made within 60 s or 100 s, but I think I used the trick you are referring to. · 1 year, 10 months ago

Yes its 1-x^6 · 2 years, 4 months ago

1-x^3 · 2 years, 4 months ago