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burhan101Best ResponseYou've already chosen the best response.0
dw:1350454227197:dw
 one year ago

burhan101Best ResponseYou've already chosen the best response.0
dw:1350454341729:dw
 one year ago

burhan101Best ResponseYou've already chosen the best response.0
yes i think so that doesnt cancel out tho . im making a mistake
 one year ago

terenzreignzBest ResponseYou've already chosen the best response.1
\[\huge \lim_{h \rightarrow 0}\frac{[(x+h)^{3}3](x^{3}3)}{h}\] is this it?
 one year ago

burhan101Best ResponseYou've already chosen the best response.0
yupp ! how do you make it big like that btw ?
 one year ago

terenzreignzBest ResponseYou've already chosen the best response.1
uhh, before typing in your equations and stuff, put in \huge
 one year ago

terenzreignzBest ResponseYou've already chosen the best response.1
This looks like you're taking the derivative of \[\huge x^{3}  3\]
 one year ago

terenzreignzBest ResponseYou've already chosen the best response.1
And you're to get the derivative using limits? lol, that's harsh... :D
 one year ago

terenzreignzBest ResponseYou've already chosen the best response.1
You'll realise soon that there are faster ways of getting the derivative... anyway, just evaluate the numerator and show me what you get...
 one year ago

Algebraic!Best ResponseYou've already chosen the best response.0
x^3 's cancel 3's cancel... what's left?
 one year ago

Algebraic!Best ResponseYou've already chosen the best response.0
3x^2h + 3xh^2 +h^3 all divided by h factor out an 'h' in the numerator cancel with the 'h' in the denom. now you can take the limit without issues.
 one year ago

burhan101Best ResponseYou've already chosen the best response.0
\[\huge \ \frac{ x^3+3x^2h+3xh^23x^2+3 }{h }\]
 one year ago

burhan101Best ResponseYou've already chosen the best response.0
i have an x^3 and x^2 ? :S
 one year ago

terenzreignzBest ResponseYou've already chosen the best response.1
Well that changes everything...
 one year ago

Algebraic!Best ResponseYou've already chosen the best response.0
\[\frac{ f(x+h)  f(x) }{h }\]
 one year ago

Algebraic!Best ResponseYou've already chosen the best response.0
\[\frac{(x+h)^3 3  ( x^3 3) }{h }\]
 one year ago

burhan101Best ResponseYou've already chosen the best response.0
thats why it doesnt cancel out
 one year ago

Algebraic!Best ResponseYou've already chosen the best response.0
you expanded correctly: \[\frac{ x^3 +3x^2h +3xh^2 +h^3 3  (x^3 3) }{h }\]
 one year ago

Algebraic!Best ResponseYou've already chosen the best response.0
then why are you cubing (x+h) ?
 one year ago

burhan101Best ResponseYou've already chosen the best response.0
ohhh i should square it *facepalm*
 one year ago

Algebraic!Best ResponseYou've already chosen the best response.0
\[\frac{ (x+h)^2 3 (x^23) }{h }\]
 one year ago

burhan101Best ResponseYou've already chosen the best response.0
can you help me with this one: find the equation of the tangent \[y=\frac{ x2 }{ x+2 }\] when x=0
 one year ago

burhan101Best ResponseYou've already chosen the best response.0
\[\huge \lim_{h \rightarrow 0} \frac{ (x+h)2 }{ (x+h)+2 } \frac{ x2 }{ x+2 }\]
 one year ago

terenzreignzBest ResponseYou've already chosen the best response.1
Equation of the tangent involves derivatives, right?
 one year ago

terenzreignzBest ResponseYou've already chosen the best response.1
Quotient rule? Ever dabbled with it?
 one year ago

burhan101Best ResponseYou've already chosen the best response.0
no we're not allowed to use that yet .
 one year ago

terenzreignzBest ResponseYou've already chosen the best response.1
Here, I don't think I have the attention span to type this out o.O http://www.math.hmc.edu/calculus/tutorials/quotient_rule/proof.pdf
 one year ago

terenzreignzBest ResponseYou've already chosen the best response.1
You're allowed to use anything as long as you can prove it ;)
 one year ago

burhan101Best ResponseYou've already chosen the best response.0
my tests always state "Only using method thought in class" i know that quotient rule is so much faster
 one year ago

burhan101Best ResponseYou've already chosen the best response.0
and we we're never thought that in class yet
 one year ago

terenzreignzBest ResponseYou've already chosen the best response.1
Well, don't despair :D I'll see what I can do... To get the equation of the tangent line, first we need a slope. to get that slope, we need the derivative. So what's the derivative (go ahead and express it first in limitform)
 one year ago

burhan101Best ResponseYou've already chosen the best response.0
\[\huge \lim_{h \rightarrow o}\frac{ (x+h)2 }{ (x+h)+2 }  \frac{ x2 }{ x+2 }\]
 one year ago

terenzreignzBest ResponseYou've already chosen the best response.1
nope... you forgot that all that must also be divided by h... small details, but no less important...
 one year ago

terenzreignzBest ResponseYou've already chosen the best response.1
tsk \[\huge \lim_{h \rightarrow 0}\frac{\frac{ (x+h)2 }{ (x+h)+2 }  \frac{ x2 }{ x+2 }}{h}\]
 one year ago

terenzreignzBest ResponseYou've already chosen the best response.1
Right, well this can also be written as \[\lim_{h \rightarrow 0}\frac{1}{h}\left( \frac{ (x+h)2 }{ (x+h)+2 }  \frac{ x2 }{ x+2 } \right)\]
 one year ago

terenzreignzBest ResponseYou've already chosen the best response.1
now \[\lim_{h \rightarrow 0}\frac{1}{h}\frac{\left[ \left( x+h \right)2 \right]\left( x+2 \right)\left[ \left( x+h \right)+2 \right]\left( x2 \right)}{\left[ \left( x+h \right)+2 \right]\left( x+2 \right)}\] o.O
 one year ago

burhan101Best ResponseYou've already chosen the best response.0
wait, how did you get rid of those fractions ?
 one year ago

terenzreignzBest ResponseYou've already chosen the best response.1
Like magic :P \[\frac{a}{b}+\frac{c}{d}=\frac{ad+bc}{bd}\]
 one year ago

terenzreignzBest ResponseYou've already chosen the best response.1
Hey, there's nothing you can cancel...
 one year ago

burhan101Best ResponseYou've already chosen the best response.0
then expansion and cancelling out the like terms
 one year ago

terenzreignzBest ResponseYou've already chosen the best response.1
Nothing that would you do you much good, anyway... Here's a tricky bit of manipulation \[\lim_{h \rightarrow 0}\frac{1}{h}\frac{\left[ \left( x+h \right)2 \right]\left( x+2 \right)(x2)(x+2)+(x2)(x+2)\left[ \left( x+h \right)+2 \right]\left( x2 \right)}{\left[ \left( x+h \right)+2 \right]\left( x+2 \right)}\]
 one year ago

terenzreignzBest ResponseYou've already chosen the best response.1
All right, scratch everything, I overlooked one important detail...
 one year ago

terenzreignzBest ResponseYou've already chosen the best response.1
You only need to get its slope on the specific case where x = 0 right?
 one year ago

terenzreignzBest ResponseYou've already chosen the best response.1
Use this definition of derivative instead: \[f'(c)=\lim_{x \rightarrow c}\frac{f(x)f(c)}{xc}\]
 one year ago

terenzreignzBest ResponseYou've already chosen the best response.1
Sorry for this extremely late reply, I was busy with something :( c is 0.
 one year ago
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