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Hello,
My function f(x) satisfies : x*exp(- f(x)) + exp(-2*f(x)) = 3*(x+1). How to plot the function f(x) ?
Thanks

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Walter Roberson
Walter Roberson 2019-3-3

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If you have the symbolic toolbox, then you can construct an equality but replace f(x) with a variable such as fx. Solve for fx. My tests show there as being two solutions. The lower bound is 2*sqrt(6)-6

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Abdoulaye Thiam
Abdoulaye Thiam 2019-3-4
编辑：Walter Roberson 2019-3-4
Thanks !
This is what you are saying. How do you found the lower bound 2*sqrt(6)-6 ?
syms x fz
>> solve( x*exp(-fz)+exp(-2*fz)-3*(x+1),fz)
ans =
log((x - (x^2 + 12*x + 12)^(1/2))/(6*(x + 1)))
log((x + (x^2 + 12*x + 12)^(1/2))/(6*(x + 1)))
Walter Roberson
Walter Roberson 2019-3-4
You have a square root. If the value inside the square root is negative then you get a complex result. So you have a boundary when the square root is 0, which occurs at the location I indicated.
Abdoulaye Thiam
Abdoulaye Thiam 2019-3-4
Thanks

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