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for the functions f(x)= 2x/(x3), compare the slopes of the tangents
i) at the points where x=3.5 and x=20
how do i do this?
 one year ago
 one year ago
for the functions f(x)= 2x/(x3), compare the slopes of the tangents i) at the points where x=3.5 and x=20 how do i do this?
 one year ago
 one year ago

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imron07Best ResponseYou've already chosen the best response.0
Can you find the first derivative of f(x)
 one year ago

sabika13Best ResponseYou've already chosen the best response.0
for x=3.5, it is 14 and for x=20 is 2.36
 one year ago

imron07Best ResponseYou've already chosen the best response.0
That's the slope of tangents at that points. (If you did find f'(x) correctly :))
 one year ago

sabika13Best ResponseYou've already chosen the best response.0
the answer says 24 for 3.5 tho :S
 one year ago

imron07Best ResponseYou've already chosen the best response.0
Tho? :? \[f'(x)=\frac{2(x3)2x}{(x3)^2}\\f'(3.5)=24 \]
 one year ago

sabika13Best ResponseYou've already chosen the best response.0
though*.. I dont get it.. what did you do?
 one year ago

imron07Best ResponseYou've already chosen the best response.0
I thought it was some new math symbol. If f(x)=u/v then f'(x)=(u'vuv')/v^2 Here, u=2x u'=2 v=x3 v'=1
 one year ago

mark_o.Best ResponseYou've already chosen the best response.1
@ sabika13 did you get it? any question here?
 one year ago

mark_o.Best ResponseYou've already chosen the best response.1
use the quotient rule here
 one year ago

mark_o.Best ResponseYou've already chosen the best response.1
d(u/v)dx=(v du/dx  u dv/dx)/v^2
 one year ago

mark_o.Best ResponseYou've already chosen the best response.1
for y= 2x/(x3), let u =2x and v=(x3) now do the quotient rule
 one year ago

mark_o.Best ResponseYou've already chosen the best response.1
@ sabika13 are you following now here?
 one year ago

sabika13Best ResponseYou've already chosen the best response.0
ivenever heard of the quotient rule.. or imforgetting..
 one year ago

sabika13Best ResponseYou've already chosen the best response.0
what does d and v stand for :S
 one year ago

mark_o.Best ResponseYou've already chosen the best response.1
oh i see, are you in algebra class now?
 one year ago

mark_o.Best ResponseYou've already chosen the best response.1
yes, do you know limits?
 one year ago

mark_o.Best ResponseYou've already chosen the best response.1
ok advance functions, im sure you already done limits of a function
 one year ago

sabika13Best ResponseYou've already chosen the best response.0
im not sure if idid.. or what that is
 one year ago

mark_o.Best ResponseYou've already chosen the best response.1
\[\lim _{x>0}\frac{ f(x+ \Delta x )f(x) }{ \Delta x }\]
 one year ago

mark_o.Best ResponseYou've already chosen the best response.1
do that limit as x approach to zero and you will arrived at f'(x)=6/(x3)^2 then you plug in x=3.5 and x=20 that is f'(3.5)=24 and f'(20)=0.021 and for f(3.5)=14 and f(20)= 3.36
 one year ago
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