Math Is Fun Forum
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#1 2012-06-21 02:41:22
- schooeric
- Member
- Registered: 2012-06-21
- Posts: 8
hey im new and need help with these 2 questions..
find f(x) if f(x)=√x^3-x all of that is under square root symbol
and
find d/dw (w+1) cube root√2w+1/ w+w^3 all of the 2w+1 is under the cube root
thanks guys!
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#2 2012-06-21 02:49:41
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: hey im new and need help with these 2 questions..
Hi schooeric;
Welcome.
find f(x) if f(x)=√x^3-x all of that is under square root symbol
Did you leave something out of the question?
If you want f'(x) it is easily obtainable through the chain rule.
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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#3 2012-06-21 03:02:23
- TheDude
- Member
- Registered: 2007-10-23
- Posts: 361
Re: hey im new and need help with these 2 questions..
Based on the second question he probably wants f'(x)?
For the first question use the chain rule. Rewrite f(x) like this:
Then
Try the second one on your own, ask if you get stuck or if you don't understand what I did for the first question.
Wrap it in bacon
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#4 2012-06-21 03:09:36
- schooeric
- Member
- Registered: 2012-06-21
- Posts: 8
Re: hey im new and need help with these 2 questions..
thank you bobbym and thank you dude! i will try the second one using chain rule hold on.
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#5 2012-06-21 03:11:32
- schooeric
- Member
- Registered: 2012-06-21
- Posts: 8
Re: hey im new and need help with these 2 questions..
nevermind the 2nd question uses product rule, quotient rule , and chain rule
i just have to find the derivative of the equation
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#6 2012-06-21 03:14:28
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: hey im new and need help with these 2 questions..
Hi schooeric;
How are you doing with the second one?
Is that it?
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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#7 2012-06-21 03:16:35
- schooeric
- Member
- Registered: 2012-06-21
- Posts: 8
Re: hey im new and need help with these 2 questions..
hey
where does the 2 come from in the denominator?
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#8 2012-06-21 03:18:36
- schooeric
- Member
- Registered: 2012-06-21
- Posts: 8
Re: hey im new and need help with these 2 questions..
yes that is correct except the denominator should be w+w^3
but it doesnt really matter 
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#9 2012-06-21 03:19:21
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: hey im new and need help with these 2 questions..
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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#10 2012-06-21 03:20:17
- schooeric
- Member
- Registered: 2012-06-21
- Posts: 8
Re: hey im new and need help with these 2 questions..
great i understand thanks!
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#11 2012-06-21 03:22:50
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: hey im new and need help with these 2 questions..
is more tedious leading to a long answer.
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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#12 2012-06-21 03:26:32
- schooeric
- Member
- Registered: 2012-06-21
- Posts: 8
Re: hey im new and need help with these 2 questions..
i would use quotient rule first then product rule then chain rule correct?
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#13 2012-06-21 03:27:47
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: hey im new and need help with these 2 questions..
Hi;
You could use my formula in post #11.
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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#14 2012-06-21 03:32:19
- schooeric
- Member
- Registered: 2012-06-21
- Posts: 8
Re: hey im new and need help with these 2 questions..
alrighty thank you!
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#15 2012-06-21 03:33:16
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: hey im new and need help with these 2 questions..
Hi;
Let me know what you get for an answer and I will check with mine.
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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