How do i supposed to do this quickly without a calculator? | Mathematics | Page 1

cerulean gull Feb 25, 2023, 3:53 AM

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How would i quickly find the cube root of 216^2

twilit girderBOT Feb 25, 2023, 3:53 AM

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cerulean gull Feb 25, 2023, 3:53 AM

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I have no idea how my teacher expects me to quickly find the cube root of 46656 without a calculator

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Like am i doing this right or?

mighty dirge Feb 25, 2023, 3:59 AM

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216=6^3, (216^2)^1/3= [(6^3)^2]^1/3=6^2=36

for the second one you put you know 27=3^3 then (27^2)^1/3)=3^2 by applying some exponent rules. btw for a cube root it wouldnt be plus or minus, just +

cerulean gull Feb 25, 2023, 4:00 AM

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HUH ❓

mighty dirge Feb 25, 2023, 4:00 AM

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is it the first bit thats troubling? I can use tex if it would be a bit clearer

cerulean gull Feb 25, 2023, 4:02 AM

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So like this?

mighty dirge Feb 25, 2023, 4:02 AM

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yeah, but just +9

cerulean gull Feb 25, 2023, 4:02 AM

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odd roots are only +?

mighty dirge Feb 25, 2023, 4:03 AM

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the only time a cube is negative is if the number youre cubing is negative

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so the cube root of a positive is always positive

cerulean gull Feb 25, 2023, 4:04 AM

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Thank you happy_heart_eyes

mighty dirge Feb 25, 2023, 4:05 AM

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np

cerulean gull Feb 25, 2023, 4:07 AM

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.solved

#How do i supposed to do this quickly without a calculator?