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# C2 Logs watch

1. Solve: Log2x + Log4x = 2

I did 1/Logx2+ 1/Logx4 = 2, but am now stuck on how to proceed.
2. change of base rule?
3. (Original post by sulaimanali)
change of base rule?
What do you mean?
4. (Original post by Desultory)
What do you mean?
Have you learnt the change of base rule for logarithms?
5. (Original post by RDKGames)
Have you learnt the change of base rule for logarithms?
well clearly they haven't
6. (Original post by ZiggyStardust_)
well clearly they haven't
...or they forgotten that they have.
7. it is a thing:

logax ≡ { logbx } / logba

for instance

log28 = { log168 } / log162

3 = (3/4) / (1/4)
8. (Original post by the bear)
it is a thing:

logax ≡ { logbx } / logba

for instance

log28 = { log168 } / log162

3 = (3/4) / (1/4)
I know that, but I still dont know how to solve it?
9. (Original post by Desultory)
I know that, but I still dont know how to solve it?
Post your attempt. I recommend switching into base 2.
10. (Original post by RDKGames)
Have you learnt the change of base rule for logarithms?
Ihave learnt them all
11. (Original post by RDKGames)
Post your attempt. I recommend switching into base 2.
I did that. I got up to:
Log24 + 1 = 2Logx4
12. (Original post by Desultory)
I did that. I got up to:
Log24 + 1 = 2Logx4
OK... so then what is the value of ? Get the form then exponentiate with an appropriate base and solve from there.

Alternatively;
Spoiler:
Show

You should know that so your equation becomes which is easier to solve
13. (Original post by RDKGames)
OK... so then what is the value of ? Get the form then exponentiate with an appropriate base and solve from there.

Alternatively;
Spoiler:
Show

You should know that so your equation becomes which is easier to solve

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