Can someone help me solve this for my son? I have gone blank!

I need to solve this for Y.

C.X^Y = P.Y

thanks

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- June 14th 2013, 02:23 AMMarkthedadhelp for my son
Can someone help me solve this for my son? I have gone blank!

I need to solve this for Y.

C.X^Y = P.Y

thanks - June 14th 2013, 02:38 AMemakarovRe: help for my son
As far as I know, Y(X) cannot be expressed in elementary functions in general.

- June 14th 2013, 03:13 AMMINOANMANRe: help for my son
Mark.. Emakarov is right

you cannot express y as an algebraic expression ...since it is trancedental.

such type of equations can be solved only by approximation or graphically . - June 14th 2013, 03:21 AMMarkthedadRe: help for my son
thanks guys. I thought I was losing it, but what you say makes sense.

- June 14th 2013, 08:21 AMHallsofIvyRe: help for my son
so the equation can be written as or . Let Z= -Yln(X). Then and so the equation becomes and then .

Now apply "Lambert's W function" to both sides. "Lambert's W function" is**defined**as the inverse function to so . Of course, "Lambert's W function" is NOT an "elementary function" so emakarov is completely correct.