Having trouble with this one.

Guys,

I am new here so please forgive my ignorance.

Need help with the following:

Y = A*ln(B*e^{c*x} - D*Y)

Where A, B, C, D are constants. I would like to determine the if there is a 20% change in "x" what is the corresponding change/impact on "Y"?

Thanks.

Re: Having trouble with this one.

Quote:

Originally Posted by

**Joesph** Guys,

I am new here so please forgive my ignorance.

Need help with the following:

Y = A*ln(B*e^{c*x} - D*Y)

Where A, B, C, D are constants. I would like to determine the if there is a 20% change in "x" what is the corresponding change/impact on "Y"?

Thanks.

Is it a 20% increase or decrease in x?

Re: Having trouble with this one.

Re: Having trouble with this one.

If you increase x by 20%, you end up with x + 0.2x = 1.2x, so replace x with 1.2x and see what effect this has.

Re: Having trouble with this one.

Thanks for the quick replys, but that's the part I don't know how to solve.

Re: Having trouble with this one.

Show me what you've tried. Start by replacing x with 1.2x...

Re: Having trouble with this one.

I would need to solve for "Y" first. The problem is that I do not know how to do that since both the left and right sides contain "Y"

**Y** = A*ln(B*ec*x - D***Y**)

if I simply put Y = A*ln(B*ec*1.2x - D*Y), I would still need a way to solve for "Y"

Re: Having trouble with this one.

Hello, Joesph!

Quote:

$\displaystyle \text{I would need to solve for }y\text{ first.}$ . You can't!

$\displaystyle \text{We have: }\:y \;=\;A\ln(Be^{cx} - Dy)$

$\displaystyle \text{We have a }transcendental\text{ equation.}$

$\displaystyle y\text{ is both inside and outside of a log function.}$

$\displaystyle \text{It cannot be solved for }y.$