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quick c2 maths question.

Hi, I was wondering if anyone could explain this to me please, i'm normally quite strong with powers however i'm stuggling to understand this.

When x^-4=16

how does x=+/-0.5

thanks.

Reply 1

AquilaXenon

Does that make sense to you? If the power is positive the root will be positive or negative.

Reply 2

Burton870

thanks and well up untill the last bit, when i put in the calculator 4 root 16 it comes up with 2, so how do you get 0.5 out of it?

Reply 3

Groat

Original post by AquilaXenon

Does that make sense to you? If the power is positive the root will be positive or negative.

I'm not so sure of your last statement!

If the power of x is even, then the root will be positive or negative.
If the power of x is odd, then the only root will be positive. (Assuming we're not talking about imaginary numbers).

Original post by Burton870

thanks and well up untill the last bit, when i put in the calculator 4 root 16 it comes up with 2, so how do you get 0.5 out of it?

I assume he meant to put sqrt^4(1/16), not sqrt^4(16).

(edited 13 years ago)

Reply 4

skibur

Original post by Burton870

thanks and well up untill the last bit, when i put in the calculator 4 root 16 it comes up with 2, so how do you get 0.5 out of it?

I think he meant fourth root of 1/16 which means plus-minus 1/2 :smile:

Reply 5

Burton870

ahh thanks both, makes sense now :smile:

Reply 6

AquilaXenon

Yes, thanks for that amendment, I did mean fourth root of 1/16. :smile:

Original post by Groat

Again, I was in a rush when I wrote the above, and I did mean even instead of positive when I said 'the power is positive'.

I apologise for those errors!

Reply 7

Groat

Original post by AquilaXenon

Yes, thanks for that amendment, I did mean fourth root of 1/16. :smile:

Again, I was in a rush when I wrote the above, and I did mean even instead of positive when I said 'the power is positive'.

I apologise for those errors!

No need to apologise - I just mentioned it so everyone understood correctly.