Can someone help me solve this equation

$\displaystyle e^x=x+2$

P.S

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- Dec 8th 2009, 06:30 PMPaymemoneySolving Exponential Equations
Can someone help me solve this equation

$\displaystyle e^x=x+2$

P.S - Dec 8th 2009, 07:19 PMmybrohshi5
Are you sure that is the correct problem? Just making sure cause i just took a shot at it and i cannot figure it out....

- Dec 8th 2009, 07:33 PMProve It
- Dec 8th 2009, 07:38 PMmybrohshi5
- Dec 8th 2009, 07:40 PMPaymemoney
yeh just looked at the question it says you need a graphics calculator to solve this one.

- Dec 8th 2009, 09:01 PMI-Think
On a random note, a few years of college will teach you how to use the Lambert W function to solve these equations.

Lambert W function - Wikipedia, the free encyclopedia

These types of questions always pop up on the forum once in a while. I'll give links when I have the time. - Dec 9th 2009, 09:29 AMI-Think
Here's a link to a similar question that links to another similar question.

http://www.mathhelpforum.com/math-he...nequality.html - May 25th 2013, 09:55 AMYosdamRe: Solving Exponential Equations
___________-x

1 = (x + 2) e

__-2___________-x-2

-e__= - (x + 2) e____, where x >= -2

_____________-2

-x-2 = W-1( -e___)

______________-2

x = -2 - W-1( -e___) (x >= -2)

where W-1 is the negative branch of order -1 of Lambert's W function. Go to Lambert W function - Wikipedia, the free encyclopedia to find out how to compute this branch; you can use W-1(x) = ln(-x) - ln(-ln(-x)) or something more complex, depending on the accuracy required - May 25th 2013, 10:18 AMMINOANMANRe: Solving Exponential Equations
This equation cannot be solved algebraically as it is trancedendal .

you may use graphical methods or numerical ones.

I enclose a graphical one the red line y=x+2 intercepts the blue curve y=e^x at two points...with their coordinates marked in the two figures below.

Attachment 28454

Attachment 28455 - May 25th 2013, 10:42 AMYosdamRe: Solving Exponential Equations
useless and childish