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# 2E: Laws of logarithms, (3) (c) (i) watch

1. Help with (c) (i) please
2. (Original post by IFoundWonderland)

Darling, dear, just change the base of the logarithm. Not that hard..

Ultimately, you get a quadratic using y-substitution which you can solve quite simply. What course are you doing? This is a joke.
3. (Original post by Bath_Student)
Darling, dear, just change the base of the logarithm. Not that hard..
I haven't done this in about a year and am re self teaching for a resit from a *****y textbook. Idek what that means
4. (Original post by IFoundWonderland)

I wasn't going to help at first, but then I saw the puppyeyes ...

If then

5. (Original post by IFoundWonderland)

try these on your calculator and see if it gives you some clues

log base 3 of 3

log base 1.4 of 1.4
6. (Original post by IFoundWonderland)
I haven't done this in about a year and am re self teaching for a resit from a *****y textbook. Idek what that means
Alright!

So, change log(4) x into base 2, gives you log(2) x / log(2) 4. It's a rule, learn it.
log(2) 4 is 2. So, you get that log(4) x = log(2)x / 2. Multiply through by 2 to remove the 2 in the denominator. Now, then, the other log(2) x is doubled (as you multiplied through by 2), and a law of logs states that 2*log(2) x = log(2) x^2.

Now you have a quadratic, let y = log(2) x. Got it from there?!
7. (Original post by Bath_Student)
Darling, dear, just change the base of the logarithm. Not that hard..

Ultimately, you get a quadratic using y-substitution which you can solve quite simply. What course are you doing? This is a joke.
that is a very unhelpful comment.
8. (Original post by atsruser)
I wasn't going to help at first, but then I saw the puppyeyes ...

If then

Are you drunk?
9. (Original post by Bath_Student)
Darling, dear, just change the base of the logarithm. Not that hard..

Ultimately, you get a quadratic using y-substitution which you can solve quite simply. What course are you doing? This is a joke.
I do the IB.

(Original post by atsruser)
I wasn't going to help at first, but then I saw the puppyeyes ...

If then

(Original post by maggiehodgson)
try these on your calculator and see if it gives you some clues

log base 3 of 3

log base 1.4 of 1.4

The correct answer is 1/4. Also it is a non calculator question *sigh*
10. (Original post by IFoundWonderland)

The correct answer is 1/4. Also it is a non calculator question *sigh*
AHHH!!!!!!!!!!!

I reiterate:

Alright!

So, change log(4) x into base 2, gives you log(2) x / log(2) 4. It's a rule, learn it.
log(2) 4 is 2. So, you get that log(4) x = log(2)x / 2. Multiply through by 2 to remove the 2 in the denominator. Now, then, the other log(2) x is doubled (as you multiplied through by 2), and a law of logs states that 2*log(2) x = log(2) x^2.

Now you have a quadratic, let y = log(2) x. Got it from there?!
11. (Original post by Bath_Student)
Darling, dear, just change the base of the logarithm. Not that hard..

Ultimately, you get a quadratic using y-substitution which you can solve quite simply. What course are you doing? This is a joke.
no need to be so patronising an unpleasant

good luck wonderland xxx
12. (Original post by IFoundWonderland)
I do the IB.
In the UK?
13. (Original post by IFoundWonderland)
I do the IB.

The correct answer is 1/4. Also it is a non calculator question *sigh*
Well, I was just trying to get you to experiment to see that log to base a of a is 1.

Form that you should be able to do something with line 1.
14. (Original post by Bath_Student)
When women ransack the mathematics thread!
how evil of them
tbf i don't know anything about maths so i'll leave lol just came cos wonderland is here
jamestg
Student403
TeeEm
SeanFM
15. (Original post by CoolCavy)
how evil of them
tbf i don't know anything about maths so i'll leave lol just came cos wonderland is here
Damnit I answered her question. If her IQ is larger then 3, then she'll be fine.
16. (Original post by Bath_Student)
AHHH!!!!!!!!!!!

I reiterate:

Alright!

So, change log(4) x into base 2, gives you log(2) x / log(2) 4. It's a rule, learn it.
log(2) 4 is 2. So, you get that log(4) x = log(2)x / 2. Multiply through by 2 to remove the 2 in the denominator. Now, then, the other log(2) x is doubled (as you multiplied through by 2), and a law of logs states that 2*log(2) x = log(2) x^2.

Now you have a quadratic, let y = log(2) x. Got it from there?!
Um

So when the x is squared its the equivalent of the whole log being squared?

I didn't realise that :/

Christ I'm so confused rn and my notes look so messy
17. (Original post by the bear)
that is a very unhelpful comment.
I already spent my bear rep™ today it seems… PRSOM.
18. (Original post by IFoundWonderland)
Um

So when the x is squared its the equivalent of the whole log being squared?

I didn't realise that :/

Christ I'm so confused rn and my notes look so messy
n*log a = log a^n. You must have seen that before?

Therefore, 2 log(2) x = log(2) x^2 .
19. (Original post by CoolCavy)
how evil of them
tbf i don't know anything about maths so i'll leave lol just came cos wonderland is here
jamestg
Student403
TeeEm
SeanFM

20. (Original post by CoolCavy)
how evil of them
tbf i don't know anything about maths so i'll leave lol just came cos wonderland is here
jamestg
Student403
TeeEm
SeanFM
teaching at present

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