# C2 Log Question - Please help me and explain

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Given that Log

a) Log

So far I have this:

= Log

And then I don't know how to continue from there, can you please explain why to me, referencing log laws so I can understand why you have done what you have done.

b) Log

So far I have this:

= Log

And then I don't know how to continue from there, can you please explain why to me, referencing log laws so I can understand why you have done what you have done.

Thanks a lot! I really struggle with logs.

_{2}x = a, find in terms of a, the simplest form of:a) Log

_{2(}16x )So far I have this:

= Log

_{2}(16) + Log_{2}(X)And then I don't know how to continue from there, can you please explain why to me, referencing log laws so I can understand why you have done what you have done.

b) Log

_{2}(x^4 / 2)So far I have this:

= Log

_{2}(x^4) - Log_{2}(2)And then I don't know how to continue from there, can you please explain why to me, referencing log laws so I can understand why you have done what you have done.

Thanks a lot! I really struggle with logs.

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#2

Do you have the answers for the questions? I think the first one might be 4a and would the second one be (a+1)/4? If I'm right I'll gladly explain

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(Original post by

Do you have the answers for the questions? I think the first one might be 4a and would the second one be (a+1)/4? If I'm right I'll gladly explain

**takurino**)Do you have the answers for the questions? I think the first one might be 4a and would the second one be (a+1)/4? If I'm right I'll gladly explain

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#4

(Original post by

The answer for part a is: 4 + a and the answer for part 2 is: 4a - 1

**blobbybill**)The answer for part a is: 4 + a and the answer for part 2 is: 4a - 1

For part 2 log2(x^4) - log2(2) is correct. We know log2(2) = 1 and you can re-write log2(x^4) as 4log2(x) (by moving the power infront) so that would equal 4a. So you would have 4a - 1.

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#5

you started it correctly!

basically... Log

this is because we can take powers of the number inside to outside the Log.

the reason 4Log

hence.. 4 * 1 = 4

hence... 4Log

thanks this is good revision, i'm resitting maths core 2

edit: you can cheat and put Log

edit2: using the knowledge of the power law, you can do part (b) now, try it yourself. good luck

basically... Log

_{2}(16) = Log_{2}(2^4) = 4Log_{2}(2) = 4this is because we can take powers of the number inside to outside the Log.

the reason 4Log

_{2}(2) = 4 is because Log_{2}(2) = 1hence.. 4 * 1 = 4

hence... 4Log

_{2}(2) + Log_{2}(X) = 4 + athanks this is good revision, i'm resitting maths core 2

edit: you can cheat and put Log

_{2}(16) in your calculator to get = 4 though understanding is better just in case the actual exam contains algebra or somethingedit2: using the knowledge of the power law, you can do part (b) now, try it yourself. good luck

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(Original post by

okay I see what it was looking for now aha. so for the first one you broke it into log2(16) + log2(x) and we know what log2(16) = 4. we also know log2(x) = a because we are given that information so it would be 4+a.

For part 2 log2(x^4) - log2(2) is correct. We know log2(2) = 1 and you can re-write log2(x^4) as 4log2(x) (by moving the power infront) so that would equal 4a. So you would have 4a - 1.

**takurino**)okay I see what it was looking for now aha. so for the first one you broke it into log2(16) + log2(x) and we know what log2(16) = 4. we also know log2(x) = a because we are given that information so it would be 4+a.

For part 2 log2(x^4) - log2(2) is correct. We know log2(2) = 1 and you can re-write log2(x^4) as 4log2(x) (by moving the power infront) so that would equal 4a. So you would have 4a - 1.

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#7

(Original post by

How do you "know log2(x) = a because we are given that information"? I don't see that information in the question. And also, how does that make it 4+a?

**blobbybill**)How do you "know log2(x) = a because we are given that information"? I don't see that information in the question. And also, how does that make it 4+a?

Hope this helps!

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#8

**blobbybill**)

How do you "know log2(x) = a because we are given that information"? I don't see that information in the question. And also, how does that make it 4+a?

So, you've split into

By the definition of the log,

Therefore, , because

So

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#9

(Original post by

Re-read your OP. In the very first line, you wrote "Let ".

So, you've split into

By the definition of the log,

Therefore, , because

So

**K-Man_PhysCheM**)Re-read your OP. In the very first line, you wrote "Let ".

So, you've split into

By the definition of the log,

Therefore, , because

So

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#10

(Original post by

Damn how do you get all those fancy effects

**takurino**)Damn how do you get all those fancy effects

Here is a link to the information page: https://www.thestudentroom.co.uk/wiki/LaTex

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#11

(Original post by

I have used LaTeX, a piece of mathematics text software that has been integrated into TSR.

Here is a link to the information page: https://www.thestudentroom.co.uk/wiki/LaTex

**K-Man_PhysCheM**)I have used LaTeX, a piece of mathematics text software that has been integrated into TSR.

Here is a link to the information page: https://www.thestudentroom.co.uk/wiki/LaTex

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