# a quick P2 exponentials question

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#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)
0
15 years ago
#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
0
15 years ago
#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
0
15 years ago
#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.
0
15 years ago
#5
that is quite funny....
0
15 years ago
#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.
0
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