This equation is NOT exact, correct?

  • Thread starter darryw
  • Start date
In summary, the given equation is not exact as M_y is not equal to N_x. However, the rearranged form shows that the equation is very close to being exact and may have been caused by a minor mistake.
  • #1
darryw
127
0

Homework Statement


(2y^2 - 4x + 5) dx = (4-2y+4xy)dy

i divided by dx and rearranged...

(-2y^2 + 4x - 5) + (4-2y+4xy)dy/dx
this is M....and this is N

then took partial derivatives...

M_y = -4y

N_x = 4y

M_y not equal to N_x, therefore not exact..

but it is so close that i suspect i am making some mistake..

??



Homework Equations





The Attempt at a Solution

 
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  • #2
Correct, it's not exact. Be careful, though - you started with an equation and lost the = in your next line.

Here's a better rearrangement.

(2y^2 - 4x + 5) dx + (-4 + 2y - 4xy)dy = 0
(...M...)...(...N...)
 
  • #3
thANKS.. shouldve been..
(-2y^2 + 4x - 5) + (4-2y+4xy)dy/dX = 0
 

1. Why is this equation not exact?

An equation is considered "exact" when it is able to be solved directly without any additional steps or approximations. If an equation is not exact, it means that it cannot be solved in this manner and requires additional steps to find a solution.

2. Can an equation be both exact and incorrect?

No, an equation can either be exact or incorrect. An exact equation is one that is able to be solved directly, while an incorrect equation is one that does not have a valid solution.

3. How do I know if an equation is exact or not?

An equation is considered exact if it can be solved directly without any additional steps or approximations. If an equation requires additional steps or approximations to find a solution, it is not considered exact.

4. What does it mean if an equation is not correct but still exact?

If an equation is not correct but still exact, it means that the solution may be valid, but there may be errors or mistakes in the equation itself. This can happen if there are typos, missing terms, or other errors in the equation.

5. How can I solve an equation that is not exact?

If an equation is not exact, it may require additional steps or approximations to find a solution. This can include using numerical methods, approximations, or other techniques to solve the equation. It is important to carefully follow the steps and use appropriate methods to ensure an accurate solution is obtained.

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