| Blogs > FragKrag |
|
FragKrag
United States11554 Posts
New Problem:X^3+Y^3=125 dy/dx =? a. -x/y b.-x/5y c. y/x d. x/(y-5) e. x/y Well, I thought it was -(x/y)^2, but it's not on there. I think that it should be negative, and there should not be a 5, which leaves me -x/y, which is x^2+y^2=C a. [8,10) b. (2,10) c. [2,10] d. [2,10) e. (2,10] halps would be appreciated <3 Edit: What we got is that since [8,10) has a continuous slope of 1, it's right.   | ||
|
Saracen
United States5139 Posts
if the sharp point from the absolute value is included in your set of points, then no if not, then yes | ||
|
doghunter
United States23 Posts
| ||
|
Avidkeystamper
United States8556 Posts
| ||
|
FragKrag
United States11554 Posts
| ||
|
doghunter
United States23 Posts
| ||
|
vAltyR
United States581 Posts
man, that's a *precalc* question? we never covered that until calculus. in fact, i never even heard the word "derivative" until i opened a calc book. | ||
|
thunk
United States6233 Posts
On October 01 2008 13:32 doghunter wrote: There's no limit from the left side, so you can't say that there is a limit at x=8 It's continuous and the limit as x approaches 8 exists. It's just no differentiable because the derivative from the right and the derivative from the left are inequal. | ||
|
Purind
Canada3562 Posts
| ||
|
SIUnit
China288 Posts
| ||
|
FragKrag
United States11554 Posts
| ||
|
skyglow1
New Zealand3962 Posts
x^3+y^3=125 Differentiation both sides by x: 3x^2+d(y^3)/dx=0 Since y is a function of x, and using chain rule: d(y^3)/dx = 3y^2 x dy/dx So you get: 3x^2 + 3y^2 x dy/dx = 0 And rearranging: dy/dx = -3x^2/3y^2 [Edit] I'm a retard -_- | ||
|
SaveYourSavior
United States1071 Posts
but a seems to be the right answer since it seems the most right | ||
|
Divinek
Canada4045 Posts
On October 22 2008 13:46 skyglow1 wrote: Use implicit differentiation which involves chain rule. x^3+y^3=125 Differentiation both sides by x: 3x^2+d(y^3)/dx=0 Since y is a function of x, and using chain rule: d(y^3)/dx = 3y^2 x dy/dx So you get: 3x^2 + 3y^2 x dy/dx = 0 And rearranging: dy/dx = -3x^2/3y^2 = -x/y so the answer should be a) Implicit differentiation is in pre calc? | ||
|
Ecael
United States6703 Posts
If memory serves schools in Taiwan covered power rule to implicit differentiation in precalc, at least that's what I recall of what my friends/parents/family's talks of how they had it tough :p EDIT - It'd be hilarious when OP posts to say how he isn't at Taiwan though.  | ||
|
FragKrag
United States11554 Posts
I'm taking "PreCalculus". It's the course name, but the book has PreCalc and Calc I so lol tt;; anyways, how can you go from -(x/y)^2 to -x/y? ?:/ | ||
|
skyglow1
New Zealand3962 Posts
| ||
|
FragKrag
United States11554 Posts
Today my math teacher tells me that "abcde" is a choice when you cant find the answer. --; | ||
|
onihunter
United States515 Posts
On October 23 2008 09:49 FragKrag wrote: ;_________; Today my math teacher tells me that "abcde" is a choice when you cant find the answer. --; Nice, would explain a lot about why I couldn't figure this problem out lol. And man I hate it when math questions have "None of the above" as a choice. | ||
|
Ecael
United States6703 Posts
On October 23 2008 09:49 FragKrag wrote: ;_________; Today my math teacher tells me that "abcde" is a choice when you cant find the answer. --; Ah good, I was going a bit insane and trying to log this through to solve earlier. | ||
| ||
|
|
Kung Fu Cup
Cure vs Reynor
Classic vs herO
RotterdaM238
IPSL
ZZZero vs rasowy
Napoleon vs KameZerg
OSC
BSL 21
Tarson vs Julia
Doodle vs OldBoy
eOnzErG vs WolFix
StRyKeR vs Aeternum
Sparkling Tuna Cup
RSL Revival
Reynor vs sOs
Maru vs Ryung
Kung Fu Cup
WardiTV Korean Royale
BSL 21
JDConan vs Semih
Dragon vs Dienmax
Tech vs NewOcean
TerrOr vs Artosis
IPSL
Dewalt vs WolFix
eOnzErG vs Bonyth
[ Show More ] |
|
|
EPT
