Differential Equations - Find equation of line

In summary, the equation of the curve passing through the point (3,-2) with a slope of (x^2 + y^2)/(y^3 - 2xy) is (1/3)x^3 - (1/4)y^4 + xy^2 = 17.
  • #1
qw111
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Homework Statement



A curve passing through (3,-2) has a slope given by (x^2 + y^2)/(y^3 - 2xy). Find the equation of the curve.

Homework Equations





The Attempt at a Solution



My first thought was to plug in the points (3,-2) into the slope equation and plug them into the line equation (y - y1) = m(x - x1). Is that wrong? Seemed too easy for it to be a problem for differential equations..

So, I found that i could make the slope equation into an exact equation and solved for it.
I found that the answer i get is:
with c = -17
f(x,y) = x^3/3 + xy^2 - y^4/4 - 17
However that is not the equation of the curve. Is that the equation of the tangent line at (3,-2)?
I am stuck at this point, I am pretty sure I am done with 90% of the work, but I can't seem to figure out the equation of the curve from here on.
 
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  • #2
Yes, you are pretty close, but you faltered a bit at the end.

The equation you were solving looked something like this:
Fx dx + Fy dy, where Fx = x2 + y2 and Fy = -y3 + 2xy

The solution to the equation above with the partials is F(x, y) = C, so you should have gotten (1/3)x3 - (1/4)y4 + xy2 = C.

Substitute y(3) = -2 into the equation above to find the constant C.
 
  • #3
Yes I did that, realized that C = 17 (not negative). But I am still puzzled, what is the equation of the curve?
 
  • #4
(1/3)x3 - (1/4)y4 + xy2 = 17.
 

Related to Differential Equations - Find equation of line

1) What is a differential equation?

A differential equation is a mathematical equation that describes the relationship between a function and its derivatives. It is used to model various physical phenomena in fields such as physics, engineering, and economics.

2) How do you solve a differential equation?

The general process for solving a differential equation involves finding a solution that satisfies the equation. This can be done by applying various techniques such as separation of variables, substitution, or using an integrating factor.

3) What is the equation of a straight line?

The equation of a straight line is typically written in the form y = mx + b, where m is the slope of the line and b is the y-intercept. This equation can also be written as Ax + By + C = 0, where A and B are the coefficients of x and y, and C is a constant.

4) How do you find the equation of a line given two points?

To find the equation of a line given two points, you can use the slope formula (m = (y2-y1)/(x2-x1)) to calculate the slope of the line. Then, plug in one of the points and the slope into the point-slope formula (y - y1 = m(x - x1)) to find the equation of the line.

5) Can differential equations be used to model real-world situations?

Yes, differential equations are commonly used to model and analyze real-world situations. For example, they can be used to describe the motion of objects, the growth of populations, and the flow of electric currents.

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