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C1 indices

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Reply 20
Avatar for raheem94
raheem94
13
Original post by tnetennba
You could use logarithms:
Log 4^x = Log 0.25
x Log 4 = Log 0.25
x= (Log 0.25)/(Log 4)
x=-1
:smile:


I want to make it clear to you that i didn't gave you neg rep, i don't know who gave it.

I think that you thought that i gave you a neg rep so you neg repped me, right?
Reply 21
Avatar for Waqar.
Waqar.
2
Make them both to the base of 2 and then equate the indices...

4 ^ x = 2^2x
1/4 = 2^-2

2^2x = 2^-2

equate both indices...
2x = -2
x = -1

In conclusion: Equate both bases and then equate the indices and simplify.
Reply 22
Avatar for roar558
roar558
11
Original post by Waqar.
Make them both to the base of 2 and then equate the indices...

4 ^ x = 2^2x
1/4 = 2^-2

2^2x = 2^-2

equate both indices...
2x = -2
x = -1

In conclusion: Equate both bases and then equate the indices and simplify.


The bases are fine as it is, I don't see why you are changing it to 2. It's quite easy to see it using the base 4.
(edited 12 years ago)
Reply 23
Avatar for roar558
roar558
11
Original post by raheem94
ln is in C3, while OP is studying C1 so she probably doesn't knows logarithms.


Fair enough, if I'm honest I'm not 100% clear on what's covered in each module having done a different specification.
Reply 24
Avatar for roar558
roar558
11
Original post by jessica_anne_clu
but how would you go about it? I know the answer is -1 but I don't know how you'd get it


You can show it using the ln rule however you apparently haven't been taught it yet so the other method would be comparing powers (make sure the base on both sides are equal).

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