dividing by a negative number?

👨🏻‍🏫 學術台 數學
2008-02-01 11:54 am
I don't understand how:

1/-3(cubed)

= 3 (cubed)
更新1:

Hey! I am so grateful for your attempts and it clearly got you all thinking!!! I misread the question... that way my error. It was 1 divided by 3 to the power of -3 = 3 to the power of 3. So 1/27 = 27!!! Which is obvious to me now!!! Sorry to have wasted your time guys!!!

回答 (8)

2008-02-01 11:59 am
✔ 最佳答案
You are mistaken. The two are not equivalent... unless I am misreading your math.

1/(3 to the negative 1 power) = 3
👍 1 👎 0
2008-02-01 8:17 pm
The equation is wrong. Its not suprising if you (and I) can't undestand it.
Why is it wrong?:

1. When dividing a positive number with a negative, the answer must be negative.
2. The anwer can't be bigger than 1.
👍 1 👎 0
2008-02-01 8:14 pm
Read the question again.
3 cubed is 27
So we need something for which the result is 27
(-3) cubed is -27
Could the question be - ((-3) cubed) or something equivalent?
👍 1 👎 0
2008-02-01 8:02 pm
That's not correct !?

1/-3(cubed) = 1/-27

3 (cubed) = 27
👍 1 👎 0
2008-02-01 9:52 pm
1/-3(cubed)
= 1/-3^3
= 1/-27
= -3^-3
👍 0 👎 0
2008-02-01 8:55 pm
No, I think you are mixed up with 1/x^-3 =x^3 which means 1/x-(cubed) = x (cubed). 1/-3 (cubed) =1/-27.
👍 0 👎 0
2008-02-01 8:41 pm
only works if the 3 cubed in the first expression is bracketed after the negative operator.
👍 0 👎 0
2008-02-01 8:27 pm
1/[(-3)^3] = 1/(-27) = -1/27
[1/(-3)]^3 = -1/27
👍 0 👎 0


收錄日期: 2021-05-01 09:53:35
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