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burhan101 Group TitleBest ResponseYou've already chosen the best response.0
dw:1350454227197:dw
 2 years ago

burhan101 Group TitleBest ResponseYou've already chosen the best response.0
dw:1350454341729:dw
 2 years ago

terenzreignz Group TitleBest ResponseYou've already chosen the best response.1
Lol, derivative?
 2 years ago

burhan101 Group TitleBest ResponseYou've already chosen the best response.0
yes i think so that doesnt cancel out tho . im making a mistake
 2 years ago

terenzreignz Group TitleBest 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?
 2 years ago

burhan101 Group TitleBest ResponseYou've already chosen the best response.0
yupp ! how do you make it big like that btw ?
 2 years ago

terenzreignz Group TitleBest ResponseYou've already chosen the best response.1
uhh, before typing in your equations and stuff, put in \huge
 2 years ago

terenzreignz Group TitleBest ResponseYou've already chosen the best response.1
This looks like you're taking the derivative of \[\huge x^{3}  3\]
 2 years ago

burhan101 Group TitleBest ResponseYou've already chosen the best response.0
yup that's right !
 2 years ago

terenzreignz Group TitleBest ResponseYou've already chosen the best response.1
And you're to get the derivative using limits? lol, that's harsh... :D
 2 years ago

burhan101 Group TitleBest ResponseYou've already chosen the best response.0
yess i have to
 2 years ago

terenzreignz Group TitleBest 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...
 2 years ago

Algebraic! Group TitleBest ResponseYou've already chosen the best response.0
x^3 's cancel 3's cancel... what's left?
 2 years ago

Algebraic! Group TitleBest 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.
 2 years ago

burhan101 Group TitleBest ResponseYou've already chosen the best response.0
\[\huge \ \frac{ x^3+3x^2h+3xh^23x^2+3 }{h }\]
 2 years ago

burhan101 Group TitleBest ResponseYou've already chosen the best response.0
i have an x^3 and x^2 ? :S
 2 years ago

terenzreignz Group TitleBest ResponseYou've already chosen the best response.1
Well that changes everything...
 2 years ago

Algebraic! Group TitleBest ResponseYou've already chosen the best response.0
\[\frac{ f(x+h)  f(x) }{h }\]
 2 years ago

Algebraic! Group TitleBest ResponseYou've already chosen the best response.0
what's f(x)?
 2 years ago

Algebraic! Group TitleBest ResponseYou've already chosen the best response.0
\[\frac{(x+h)^3 3  ( x^3 3) }{h }\]
 2 years ago

burhan101 Group TitleBest ResponseYou've already chosen the best response.0
no f(x)=x^23
 2 years ago

burhan101 Group TitleBest ResponseYou've already chosen the best response.0
thats why it doesnt cancel out
 2 years ago

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

Algebraic! Group TitleBest ResponseYou've already chosen the best response.0
then why are you cubing (x+h) ?
 2 years ago

burhan101 Group TitleBest ResponseYou've already chosen the best response.0
ohhh i should square it *facepalm*
 2 years ago

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

burhan101 Group TitleBest 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
 2 years ago

burhan101 Group TitleBest ResponseYou've already chosen the best response.0
\[\huge \lim_{h \rightarrow 0} \frac{ (x+h)2 }{ (x+h)+2 } \frac{ x2 }{ x+2 }\]
 2 years ago

burhan101 Group TitleBest ResponseYou've already chosen the best response.0
@terenzreignz
 2 years ago

terenzreignz Group TitleBest ResponseYou've already chosen the best response.1
Equation of the tangent involves derivatives, right?
 2 years ago

terenzreignz Group TitleBest ResponseYou've already chosen the best response.1
Quotient rule? Ever dabbled with it?
 2 years ago

burhan101 Group TitleBest ResponseYou've already chosen the best response.0
no we're not allowed to use that yet .
 2 years ago

terenzreignz Group TitleBest 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
 2 years ago

terenzreignz Group TitleBest ResponseYou've already chosen the best response.1
You're allowed to use anything as long as you can prove it ;)
 2 years ago

burhan101 Group TitleBest 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
 2 years ago

burhan101 Group TitleBest ResponseYou've already chosen the best response.0
and we we're never thought that in class yet
 2 years ago

terenzreignz Group TitleBest 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)
 2 years ago

burhan101 Group TitleBest ResponseYou've already chosen the best response.0
\[\huge \lim_{h \rightarrow o}\frac{ (x+h)2 }{ (x+h)+2 }  \frac{ x2 }{ x+2 }\]
 2 years ago

terenzreignz Group TitleBest 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...
 2 years ago

burhan101 Group TitleBest ResponseYou've already chosen the best response.0
ohh i did :$
 2 years ago

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

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

terenzreignz Group TitleBest 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
 2 years ago

burhan101 Group TitleBest ResponseYou've already chosen the best response.0
wait, how did you get rid of those fractions ?
 2 years ago

terenzreignz Group TitleBest ResponseYou've already chosen the best response.1
Like magic :P \[\frac{a}{b}+\frac{c}{d}=\frac{ad+bc}{bd}\]
 2 years ago

terenzreignz Group TitleBest ResponseYou've already chosen the best response.1
Get it now?
 2 years ago

burhan101 Group TitleBest ResponseYou've already chosen the best response.0
yeaaah ! i do
 2 years ago

burhan101 Group TitleBest ResponseYou've already chosen the best response.0
and then cancelling
 2 years ago

terenzreignz Group TitleBest ResponseYou've already chosen the best response.1
Hey, there's nothing you can cancel...
 2 years ago

burhan101 Group TitleBest ResponseYou've already chosen the best response.0
then expansion and cancelling out the like terms
 2 years ago

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

terenzreignz Group TitleBest ResponseYou've already chosen the best response.1
All right, scratch everything, I overlooked one important detail...
 2 years ago

terenzreignz Group TitleBest ResponseYou've already chosen the best response.1
You only need to get its slope on the specific case where x = 0 right?
 2 years ago

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

burhan101 Group TitleBest ResponseYou've already chosen the best response.0
whats c ?
 2 years ago

terenzreignz Group TitleBest ResponseYou've already chosen the best response.1
Sorry for this extremely late reply, I was busy with something :( c is 0.
 2 years ago
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