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Indices and Surds Hellpppppp!!!!!!!

I got this question:

Simply wy

w: 6\sqrt{6}

y: 3−5/2{3^{-5/2}}

It also says write your answer in surd form.

Please help!!!!
(edited 9 years ago)

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Original post by UnknownDude
I got this question:

Simply wy

w: √6

y: 3^(-5/2)

It also says write your answer in surd form.

Please help!!!!


ab=a×b\sqrt{ab} = \sqrt{a} \times \sqrt{b}

Split the 6
So ! Get started and show us what you did so far.
Original post by arkanm
Write 6\sqrt{6} as 2×3=2×3=21/2×31/2\sqrt{2\times 3}=\sqrt{2}\times \sqrt{3}=2^{1/2} \times 3^{1/2}. So wy=21/2×31/2×3−5/2wy = 2^{1/2} \times 3^{1/2}\times 3^{-5/2}. I think you can finish from here.

The answer is needed in surd form.
Original post by arkanm
Write 6\sqrt{6} as 2×3=2×3=21/2×31/2\sqrt{2\times 3}=\sqrt{2}\times \sqrt{3}=2^{1/2} \times 3^{1/2}. So wy=21/2×31/2×3−5/2wy = 2^{1/2} \times 3^{1/2}\times 3^{-5/2}. I think you can finish from here.


Original post by TenOfThem
ab=a×b\sqrt{ab} = \sqrt{a} \times \sqrt{b}

Split the 6


Original post by Old_Simon
So ! Get started and show us what you did so far.


Original post by Old_Simon
The answer is needed in surd form.


Firstly, thanks everyone for the replies. First time on TSR and a good impression :smile: !

So what I got so far is 2×3−4\sqrt{2}\times \sqrt{3^{-4}}
Original post by UnknownDude
Firstly, thanks everyone for the replies. First time on TSR and a good impression :smile: !

So what I got so far is 2×3−4\sqrt{2}\times \sqrt{3^{-4}}


so you need to deal with that

3−4\sqrt{3^{-4}}

What does the negative index do

What is the impact of the square root on the power of 4
Original post by UnknownDude
Firstly, thanks everyone for the replies. First time on TSR and a good impression :smile: !

So what I got so far is 2×3−4\sqrt{2}\times \sqrt{3^{-4}}

Nearly spot on.

You need a bracket around root 3.

Then tidy up. Well done !!!

Tenofthem just confusing you.
Original post by TenOfThem
so you need to deal with that

3−4\sqrt{3^{-4}}

What does the negative index do

What is the impact of the square root on the power of 4


Lol, it said leave it in surd form.

Original post by Old_Simon
Nearly spot on.

You need a bracket around root 3.

Then tidy up. Well done !!!

Tenofthem just confusing you.


Oh so is that it? Nothing big or special? How would I tidy up?
Original post by arkanm
So? xa/b=xbax^{a/b}=\sqrt[b]{x}^a

Not so anything. It needs to be in surds so it makes sense to work in surds not go to indices then back again. See ? So ?
Original post by UnknownDude
Lol, it said leave it in surd form.


yes, but you do need to simplify a little
Original post by UnknownDude
Lol, it said leave it in surd form.



Oh so is that it? Nothing big or special? How would I tidy up?

Well you need to know what root 3 to the power of minus 4 is and what to do with it.
People need to grasp that 'leave it in surd form' doesn't mean 'don't simplify in the slightest'.
Original post by Old_Simon
Well you need to know what root 3 to the power of minus 4 is and what to do with it.


Lol, can you guys just tell me the answer then I work my way to understanding it from there?

Heres the question again:

Simply wy

w:

y:

It also says write your answer in surd form.


And here's my answer:



Is everything correct, fine?
Original post by UnknownDude
Lol, can you guys just tell me the answer then I work my way to understanding it from there?

Heres the question again:



And here's my answer:



Is everything correct, fine?


That's correct but 2×3−4\sqrt{2}\times \sqrt{3^{-4}} can be simplified further.
Original post by cambo211
People need to grasp that 'leave it in surd form' doesn't mean 'don't simplify in the slightest'.

Of course. But why not do any simplifying into surd form not vice versa ?
Although this is a surd question it is the indices bit the OP is struggling with.
Original post by UnknownDude

Is everything correct, fine?


I already said that you need to tidy up the 3−4\sqrt{3^{-4}}

You would not leave a question with 16\sqrt{16} in it - you would put 4

And you need to think about the negative index and what that means
Original post by arkanm
No, because 3−4\sqrt{3^{-4}} can be simplified further. Note that x=x1/2\sqrt{x}=x^{1/2} -- does that help?


Original post by cambo211
That's correct but 2×3−4\sqrt{2}\times \sqrt{3^{-4}} can be simplified further.


So the answer would be 2×3−4/2\sqrt{2}\times {3^{-4/2}}
Original post by arkanm
No, because 3−4\sqrt{3^{-4}} can be simplified further. Note that x=x1/2\sqrt{x}=x^{1/2} -- does that help?

This is just plain out and out wrong. It may be maths but it is not the way to answer this question.
Oh yeah guys, if your wondering. My answer has to be in surd form.
Original post by UnknownDude
So the answer would be 2×3−4/2\sqrt{2}\times {3^{-4/2}}


42=2\dfrac{4}{2} = 2


Again - do you know what the negative index does?

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