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November 1st, 2011, 12:50 PM   #1
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First Deriv test, finding critical numbers of this.Need help

So I don't have class for another week and I have a question about this problem. I understand the steps in order to do this, it's just the power that messes me up while doing the algebra parts of these calc problems.

1. Find all the x-intercepts of the function f(x)= X^5 - X. Express as ordered pairs.
*The 5th power messes me up here. Can anyone walk me through how to properly do this while dealing with that 5th?

2. The y-intercept occurs at the point ____.
*I just plug the x problem into the original function to get this right?

3. The first deriv of the function: This I got to be 5X^4 - 1

4. Set the first deriv equal to zero, find the critical values of the function. Round to the thousandths place when necessary.
*I've tried this a couple different ways but I keep messing up with the 4th power up there.. I can't seem to get it right. I'm fine on the easier problems but when the powers get higher I get messed up on it.



The rest is just finding increasing/decreasing, max/mins, etc. I know how to do those.. I just have trouble finding the x-interceps in #1 and finding the critical values in #4. Can anyone help me with this? Those powers keep messing me up..

Thanks
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November 1st, 2011, 01:50 PM   #2
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Re: First Deriv test, finding critical numbers of this.Need

Quote:
Originally Posted by steelcurtain11
1. Find all the x-intercepts of the function f(x)= X^5 - X. Express as ordered pairs.
Factor:



The x-intercepts are where the function = 0:





2. The y-intercept occurs at the point x = 0, for any function. For this function it is at (0, 0).

3. Correct.

4.





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November 1st, 2011, 06:51 PM   #3
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Re: First Deriv test, finding critical numbers of this.Need

Thank you! This helped me a lot. I had something close to that, it really helped me figure out how to deal with the algebra better.
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