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November 1st, 2011, 12:50 PM  #1 
Newbie Joined: Nov 2011 Posts: 2 Thanks: 0  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 xintercepts 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 yintercept 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 xinterceps in #1 and finding the critical values in #4. Can anyone help me with this? Those powers keep messing me up.. Thanks 
November 1st, 2011, 01:50 PM  #2  
Global Moderator Joined: Oct 2008 From: London, Ontario, Canada  The Forest City Posts: 7,958 Thanks: 1146 Math Focus: Elementary mathematics and beyond  Re: First Deriv test, finding critical numbers of this.Need Quote:
The xintercepts are where the function = 0: 2. The yintercept occurs at the point x = 0, for any function. For this function it is at (0, 0). 3. Correct. 4.  
November 1st, 2011, 06:51 PM  #3 
Newbie Joined: Nov 2011 Posts: 2 Thanks: 0  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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