Question

how do you take the derivative of y=ln(x^7)

Answer 1

Chain rule
= \[7x^6/x^7\]
= \[7/x\]

Answer 2

that's what i did, but it was marked wrong...

Answer 3

\[y=ln(x^7)\]\[y=7lnx\]
\[y'=7 {1\over x }\]\[y'={7\over x}\]

Answer 4

It's right. You're teacher is wrong. It happens :)

Answer 5

Check this for "proof": http://www.wolframalpha.com/input/?i=derivative+ln%28x%5E7%29

Answer 6

Use:
\[\frac{d}{dx} \ln(...) = \frac{1}{(...)}*(...)' \]
\[\frac{d}{dx} = \frac{1}{x^{7}} * 7x^6 = \frac{7x^{6}}{x^{7}} \]

Answer 7

that was marked incorrectly as well... :-(

Answer 8

Well, what about:
\[\frac{7}{x} \]?

Answer 9

i think my teacher is wrong...

Answer 10

The derivative of \[\ln (x^7)\] has always been and always will be \[7/x\] :D

Answer 11

it's 7/x

Answer 12

You're teacher is DEFINITELY wrong. (Unless you wrote the question incorrectly)