• Support PF! Buy your school textbooks, materials and every day products via PF Here!

Implicit Differentiation Question

1. Homework Statement
I am told to find dy/dx by implicit differentiation where:
e^(x^2 * y) = x + y

2. Homework Equations
The above equation and the ln of it.


3. The Attempt at a Solution
e^(x^2 * y) = x + y
(x^2 * y)ln(e) = ln(x+y)
x^2 * y = ln(x+y)
x^2(dy/dx) + y(2x) = 1/(x+y) * (1 + dy/dx)
(dy/dx)[x^2 - 1/(x+y)] = 1/(x+y) - 2xy
dy/dx = (1/(x+y) - 2xy)/(x^2 - 1/(x+y))

or here: https://postimg.org/image/3k5ygbkxt/

This was marked wrong (online software). It doesn't care about simplest form and it was entered properly. So, what did I do wrong?
 

Attachments

fresh_42

Mentor
Insights Author
2018 Award
11,157
7,663
I got the same result without using the logarithm, only with a single quotient, i.e. expanded by ##x+y##. Maybe the missing brackets in your linear notation led to the online error. Or it is expected to write ##e^{x^2y}## instead of ##x+y## in the solution.
 
I got the same result without using the logarithm, only with a single quotient, i.e. expanded by ##x+y##. Maybe the missing brackets in your linear notation led to the online error. Or it is expected to write ##e^{x^2y}## instead of ##x+y## in the solution.
I just put it in replacing x+y with e^(x^2 * y) and it worked. Thanks!
 

Want to reply to this thread?

"Implicit Differentiation Question" You must log in or register to reply here.

Related Threads for: Implicit Differentiation Question

  • Posted
Replies
9
Views
635
  • Posted
Replies
1
Views
1K
  • Posted
Replies
10
Views
5K
Replies
10
Views
3K
Replies
2
Views
1K

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving
Top