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Math Help - How to show limit?

  1. #1
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    How to show limit?

    Could anybody help me with the following limit: ln(x^.25)/sin(x-1) as x goes to 0 from above. I am confused since ln of 0 is negative infinity. How do i do this?

    Thanks for any help.
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  2. #2
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    Re: How to show limit?

    You are correct that as x approaches zero, the numerator will approach negative infinity. So the question relies on the denominator now. You need to see if the sign will change. Have you tried plotting it?
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  3. #3
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    Re: How to show limit?

    I plotted the equation and the denominator and the equation looks to go to infinity (how do i show this without graph) and the denominator varies between -1 and 1. could you pleasee explain what you mean by "You need to see if the sign will change".

    Thanks for the reply
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  4. #4
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    Re: How to show limit?

    As x approaches zero, the denominator will approach a negative finite amount. If you have some numerator which approaches negative infinity then we have a negative over a negative giving a positive sign in the result. So it seems to me the answer is positive infinity.
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  5. #5
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    Re: How to show limit?

    ok that seems to make sense. Thank you grillage.
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