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IsTim
Group Title
Determine the equation of the tangent to the curve at a given point.
x^2+9y^2=37 (1,2)
 2 years ago
 2 years ago
IsTim Group Title
Determine the equation of the tangent to the curve at a given point. x^2+9y^2=37 (1,2)
 2 years ago
 2 years ago

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IsTim Group TitleBest ResponseYou've already chosen the best response.0
I've gotten the slope of 1/18, but I don't know if that's correct. And if so, how do I continue?
 2 years ago

IsTim Group TitleBest ResponseYou've already chosen the best response.0
So, first, dy/dx=x/dy. I then subbed in (1,2) and got 1/18.
 2 years ago

CHAD159753 Group TitleBest ResponseYou've already chosen the best response.0
Lol uhh so I cant give answers so ill just leave now but what youv done so far is correct :D
 2 years ago

IsTim Group TitleBest ResponseYou've already chosen the best response.0
I don't need the answer. I need to know what my process afterwards should be.
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
What's the derivative?
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
And Chad is in 11th grade, he won't be able to help you
 2 years ago

IsTim Group TitleBest ResponseYou've already chosen the best response.0
1. Derivative is 2x+18y(dy/dx)=0. Right? 2. I figured that out already...
 2 years ago

CHAD159753 Group TitleBest ResponseYou've already chosen the best response.0
lol ink I can give him an answer ;D
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
x^2+9y^2=37 dy/dx 37=dy/dx x^2+dy/dx 9y^2 0=2x+18y dy/dx
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
No, you won't give him the answer he's looking for. THe answer he's looking for is an explanation, because, as everyone knows, it's the explanantion that matters in calc
 2 years ago

IsTim Group TitleBest ResponseYou've already chosen the best response.0
I already have the answer in my textbook and potentially Wolfram Alpha. I need to know how to GET there though.
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
Normally at this point I try to isolate dy/dx for convenience
 2 years ago

shruti Group TitleBest ResponseYou've already chosen the best response.0
from conic section?
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
0=2x+18y dy/dx (2x)/(18y)=dy/dx x/(9y)=dy/dx
 2 years ago

IsTim Group TitleBest ResponseYou've already chosen the best response.0
Yeah, I think I did that.It's x/dy right? @ Shruti: I don't think so...
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
And, my answer agrees with your answer here.
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
Although my work here is moot, because i'm in 9th grade.
 2 years ago

IsTim Group TitleBest ResponseYou've already chosen the best response.0
Ok. Thanks for the help so far.
 2 years ago

IsTim Group TitleBest ResponseYou've already chosen the best response.0
Ok. How would I get to the answer of x+18y37=0 from knowing that the slope is 1/18?
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
If you had the derivative and wanted to get the original equation?
 2 years ago

IsTim Group TitleBest ResponseYou've already chosen the best response.0
@shruti By conics did you mean http://www.purplemath.com/modules/circle3.htm
 2 years ago

amistre64 Group TitleBest ResponseYou've already chosen the best response.0
since this is an equation of an ellipse, y can be considered an implicit function of x right?
 2 years ago

IsTim Group TitleBest ResponseYou've already chosen the best response.0
I guess. My notes only reveal the steps. This work is not from a textbook.
 2 years ago

IsTim Group TitleBest ResponseYou've already chosen the best response.0
In fact, it's not even addressed in my textbook. That's strange.
 2 years ago

amistre64 Group TitleBest ResponseYou've already chosen the best response.0
it can be .... to derive implicitly, ignore the form of the variable and treat everything as tho it acted like you normally think of deriving x^2+9y^2=37 ; just derive it all, but dont toss out the derived bits 2x x' + 18y y' = 0 now lets consider this when we derive it with respect to x x' = dx/dx = 1 y' = dy/dx like normal so, lets solve it for y'
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
If you have the derivative, and want to get the original equation, you take the antiderivative of it
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
If you're asking about taking antiderivatives (indefinite integrals), and have not yet learned about rieman sums, don't worry about the question
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
Otherwise, I might have to look into it.
 2 years ago

IsTim Group TitleBest ResponseYou've already chosen the best response.0
Y' is x/dy, which, when we sub in (1,2) is 1/18 right?
 2 years ago

dpaInc Group TitleBest ResponseYou've already chosen the best response.0
yes tim, 1/18 is right
 2 years ago

IsTim Group TitleBest ResponseYou've already chosen the best response.0
What would I do next then?
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
Well, you have a point, and a slope.
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
(1,2) > point 1/18 > slope
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
remember, y=mx+b
 2 years ago

IsTim Group TitleBest ResponseYou've already chosen the best response.0
Would I sub those into y=mx+b?
 2 years ago

dpaInc Group TitleBest ResponseYou've already chosen the best response.0
you have slope, you have a point, put it in point slope form...
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
put in the point and the slope, and then you have b
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
then, put in y=mx+b, cept don't put in that point
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
This isn't a calculus problem, this is an algebra problem, :D
 2 years ago

IsTim Group TitleBest ResponseYou've already chosen the best response.0
Sorry, what is point slope form? It's algebra? I must really have been "dumbing" down these years...
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
There's multiple ways of writing the equation for a line.
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
This is point slope: yy1=m(xx1)
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
this is slope intecept: y=mx+b
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
This is standard form: ax+by=c
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
I normally work with slope intercept, because i'm more used to it.
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
However, point slope is the fastest way to go here.
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
yy1=m(xx1) (x1,y1)=(1,2) m=1/18
 2 years ago

IsTim Group TitleBest ResponseYou've already chosen the best response.0
The answer is in the form of ax+by=c I guess, but I am also more familiar with slope intercept.
 2 years ago

IsTim Group TitleBest ResponseYou've already chosen the best response.0
Wait, I already have the slope... I know it is 1/18. But how do I get to x+18y37?
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
y1=(1/18)(x2) now, just isolate y, and distribute x
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
They have given you the point that the line must pass through, and you have found the slope,
 2 years ago

IsTim Group TitleBest ResponseYou've already chosen the best response.0
Oh. I finally understand. Thank you very much. I will call out again if I need help.
 2 years ago

IsTim Group TitleBest ResponseYou've already chosen the best response.0
Wait, 1 and 2 in y1=(1/18)(x2)/ Shouldn't it be y2=(1/18)(x1)? Because (1,2)?
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
I got it confused myself. xD
 2 years ago

IsTim Group TitleBest ResponseYou've already chosen the best response.0
Why doesn't my answer look like that provided on the sheet, which is x+18y37?
 2 years ago

IsTim Group TitleBest ResponseYou've already chosen the best response.0
Oh. I figured that out. Sorry.
 2 years ago

IsTim Group TitleBest ResponseYou've already chosen the best response.0
Thank you all for putting forth the effort to assist me.
 2 years ago

IsTim Group TitleBest ResponseYou've already chosen the best response.0
Or at the very least, looking over the question.
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
No problem :)
 2 years ago

inkyvoyd Group TitleBest ResponseYou've already chosen the best response.1
This is good premptive practice for me ;)
 2 years ago
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