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Math Help - help with natural logs

  1. #1
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    help with natural logs

    I am trying to brush up on logs and I am having a hard time finding some more challenging problems. Here is an example of one.

    ln\frac{{(2x+3)^5}{\sqrt{4-sinx}}}{{(9+e^{3x})}{(9-2x)^4}}

    I am looking to practice more problems like this one. For example, what would I do if I had a third root along with the 4-sinx?
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  2. #2
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    \ln{\frac{{(2x+3)^5}{\sqrt[3]{4-\sin{x}}}}{{(9+e^{3x})}{(9-2x)^4}}}

    5\ln(2x+3) + \frac{1}{3}\ln(4-\sin{x}) - \ln(9+e^{3x}) - 4\ln(9-2x)
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  3. #3
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    Thanks, but since you took 4-sinx out of the square root, don't you normally have to multiply that to the 1/2, so why would you then not have (1/3)(1/2)?
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    Quote Originally Posted by gammaman View Post
    I am trying to brush up on logs and I am having a hard time finding some more challenging problems. Here is an example of one.

    ln\frac{{(2x+3)^5}{\sqrt{4-sinx}}}{{(9+e^{3x})}{(9-2x)^4}}
    Please pardon my confusion, but what are you supposed to do with this? You posted this to calculus; are you supposed to differentiate the associated function?

    Thank you!
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  5. #5
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    Oh yes, i am supposed to differentiate. However as said before I need some of the more complicated ones to practice, both diff and integration. I don't mean to beg but the ones in the text book and the ones I am finding on-line are far less complicated then the ones that will be on my test.
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  6. #6
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    Quote Originally Posted by gammaman View Post
    Thanks, but since you took 4-sinx out of the square root, don't you normally have to multiply that to the 1/2, so why would you then not have (1/3)(1/2)?
    \sqrt[3]{a} = a^{\frac{1}{3}}

    \sqrt{a} = a^{\frac{1}{2}}

    see the difference?

    a radical with no index is presumed to be a square root.
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