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Given a tangent line, find f(x) 
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#1
Jul1006, 11:32 AM

P: 494

I have a homework problem as follows:
If the tangent line to y = f(x) at (4,3) passes through the point (0,2), find f(4) and f'(4). Using the slope formula and the pointslope formula, I found that the equation of the given tangent line is y = 1/4x + 2. Now I want to find f(x) so I can actually answer the question. I thought I might be able to solve for f(x) using the equation f'(a)= lim [f(x+h)  f(x)]/h h>0 and subsituting 1/4 for f'(a), but I can't get any farther than setting that up. help? please? thanks! 


#2
Jul1006, 11:53 AM

P: 925

You don't need f(x) to know what f(4) is. You're already given f(4)



#3
Jul1006, 11:55 AM

P: 494

Thank you!
I have to remember that learning calculus does not mean forgetting the very first rules of reading ordered pairs, don't I... 


#4
Jul1006, 03:14 PM

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P: 39,682

Given a tangent line, find f(x)



#5
Oct908, 03:09 PM

P: 1

what will be f'(4)?
0? 


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