how to simplify 2000^1/3?
first------2000^1/3
next part is--- "cube root 2000"
what comes next
(btw it has to be simplified not the exact cube root of 2000)
回答 (7)
✔ 最佳答案
2000^(1/3)
= ³√(2000)
= ³√(2 * 10^3)
= 10³√2
Break it down to all its prime factors, then find all the ones that come in triplets.
2000 = 2*2*2*2*5*5*5
(I use * as a multiplication sign)
There are two triplets:
2000 = 2*(2*2*2)*(5*5*5)
We use these two rules:
1) the cube root can be distributed to the factors
example: CubeRoot(216) = CubeRoot(8*27) = CubeRoot(8) * CubeRoot(27) = 2*3 = 6
2) the cube root of a triplet of factors is simply one of the factors:
example 125 = 5*5*5
CubeRoot(125) = CubeRoot(5*5*5) = 5
Therefore
CubeRoot(2000) = CubeRoot[2*(2*2*2)*(5*5*5)]
(rearranging the order does not change the product)
= CubeRoot[(2*2*2)*(5*5*5)*2]
Next, we "distribute" the cube root:
= CubeRoot(2*2*2) * CubeRoot(5*5*5) * CubeRoot(2)
We solve the triplets:
= 2*5*CubeRoot(2)
=10*CubeRoot(2)
³â2000
= ³â(1000 * 2)
RULE: = â(a*b) = âa*âb so
= ³â(1000) * ³â(2)
= 10 * ³â(2)
= 10 * 2^(1/3)
參考: :D
收錄日期: 2021-05-01 11:42:28
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