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# a quick P2 exponentials question watch

1. if i have say:

e^x + k = y

why am i not allowed to do:
take ln of both sides to get: x +lnk = lny

e^x= y -k
x=ln(y-k)
2. Well, say you have:

10 = 7 + 2

You can't do:

ln 10 = ln 7 + ln 2, try it - it doesn;t work.

If it did, then I could solve fermat's last theorum!

a^n + b^n = c^n

ln a + ln b = ln c

How can this possible be right?

It's liek squaring both sides - you must put both sides in brackets them do it:

5 = 2 + 3
but
25 =/= 4 + 9
3. (Original post by mik1a)
Well, say you have:

10 = 7 + 2

You can't do:

ln 10 = ln 7 + ln 2, try it - it doesn;t work.
not a good example lol...as 10 does not equal 7+2 anyway
4. (Original post by lgs98jonee)
not a good example lol...as 10 does not equal 7+2 anyway
darn... 7+2 = 10
not far off though.
5. that is quite funny....
6. (Original post by mik1a)
Well, say you have:

10 = 7 + 2

You can't do:

ln 10 = ln 7 + ln 2, try it - it doesn;t work.

If it did, then I could solve fermat's last theorum!
Argh, theorem damn it.

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Updated: June 16, 2004
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