CAlculus derivative help please?

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  • #1
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Homework Statement


Calculus Derivative help?
when x = 0, f=2, f '=1, g=5, g '= -4
when x = 1, f=3, f '=2, g=3, g '= -3
when x = 2, f=5, f '=3, g=1, g '= -2
when x = 3, f=10, f '=4, g=0, g '= -1
based on the above table, if a = f +2g, then a'(3) =?
please show steps.thanks


Homework Equations




if a = f +2g, then a'(3) =?

The Attempt at a Solution


a=f'+0(g')
a'(3)=f'3+0
a'(3)=4????
 

Answers and Replies

  • #2
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I don't understand what the problem is =(
 
  • #3
NascentOxygen
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based on the above table, if a = f +2g, then a'(3) =?
Does the textbook give you the correct answer?
 
  • #4
vela
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Homework Statement


Calculus Derivative help?
when x = 0, f=2, f '=1, g=5, g '= -4
when x = 1, f=3, f '=2, g=3, g '= -3
when x = 2, f=5, f '=3, g=1, g '= -2
when x = 3, f=10, f '=4, g=0, g '= -1
based on the above table, if a = f +2g, then a'(3) =?
please show steps.thanks


Homework Equations




if a = f +2g, then a'(3) =?

The Attempt at a Solution


a=f'+0(g')
You didn't differentiate this correctly. You may want to review the properties of differentiation.
a'(3)=f'3+0
a'(3)=4????
 
  • #5
20
0

Homework Statement



Calculus Derivative help?
when x = 0, f=2, f '=1, g=5, g '= -4
when x = 1, f=3, f '=2, g=3, g '= -3
when x = 2, f=5, f '=3, g=1, g '= -2
when x = 3, f=10, f '=4, g=0, g '= -1
based on the above table, if a = f +2g, then a'(3) =?
please show steps.thanks


Homework Equations




if a = f +2g, then a'(3) =?

The Attempt at a Solution


a=f'+0(g')
a'(3)=f'3+0
a'(3)=4????


can anyone just please give me the steps on how to do it and just be direct
 
  • #6
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Think about it.

a = f + 2g really means that a at 3 will equal f at 3 added to twice the value of g at 3. The latter information is given you in your table; just do the addition.

But how to calculate the derivative of a? That's where the point of the whole problem comes into play. The goal of the problem is to get you to think about one of the rules of derivatives. What rule have you learned that allows you to calculate the derivative of a sum of functions of which you already know the derivatives?
 
  • #7
HallsofIvy
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Homework Helper
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Homework Statement



Calculus Derivative help?
when x = 0, f=2, f '=1, g=5, g '= -4
when x = 1, f=3, f '=2, g=3, g '= -3
when x = 2, f=5, f '=3, g=1, g '= -2
when x = 3, f=10, f '=4, g=0, g '= -1
based on the above table, if a = f +2g, then a'(3) =?
please show steps.thanks


Homework Equations

A very relevant equation is "(af(x)+ bg(x))'= af'(x)+ bg'(x)"


if a = f +2g, then a'(3) =?

The Attempt at a Solution


a=f'+0(g')
Where did this "0" come from? a'(3)= f'(3)+ 2g'(3)

a'(3)=f'3+0
a'(3)=4????


can anyone just please give me the steps on how to do it and just be direct
 
  • #8
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can anyone just please give me the steps on how to do it and just be direct
That's not how it works here at Physics Forums. We provide help so that you can do a problem, but we don't do the work for you.
 
  • #9
eumyang
Homework Helper
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That's not how it works here at Physics Forums. We provide help so that you can do a problem, but we don't do the work for you.
To the OP: also, stop posting the same question in multiple threads. I believe that's also against the forum rules.
 
  • #10
berkeman
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(Two threads merged)
 
  • #11
NascentOxygen
Staff Emeritus
Science Advisor
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well,i think this problem will be solved in the following steps:
Indeed it can be solved that way. But it may not help the OP's understanding of how to solve further exercises of this nature.

You do no one any favors by handing them the complete solution before they have had the opportunity to be guided to achieving it for themselves.
 
  • #12
1
0
you are right about that
thanks
 

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