We'll substitute x^(ln x/ln 2) by t and we'll re-write the
equation in t:
t = 6 -
8/t
We'll multiply by t both
sides:
t^2 = 6t - 8
We'll move
all terms to one side:
t^2 - 6t + 8 =
0
Since the sum is 6 and the product is 8, we'll conclude
that the roots of the quadratic are:
t1 = 2 and t2 =
4
x^(ln x/ln 2) = t1
x^(ln
x/ln 2) = 2
But ln x/ln 2 = log 2
x
We'll take logarithms both
sides:
log2 (x^log2 x) = log2
2
We'll apply the power rule of
logarithms:
log2 (x^log2 x) =
1
(log2 x)^2 - 1 = 0
We'll
re-write the differnce of squares:
(log2 x - 1)(log2 x + 1)
= 0
log2 x - 1 = 0 => log2 x=1 => x =
2^1
x = 2
log2 x + 1 = 0
=> log2 x = -1 => x = 2^-1
x =
1/2
x^(ln x/ln 2) = t2
x^(ln
x/ln 2) = 4
log2 (x^log2 x) = log2
4
log2 (x^log2 x) = log2
2^2
log2 (x^log2 x) = 2log2
2
log2 (x^log2 x) = 2
log2
(x^log2 x) - 2 = 0
(log2 x)^2 - 2 =
0
(log2 x - sqrt2)(log2 x + sqrt2) =
0
log2 x - sqrt2 = 0
log2 x =
sqrt2 => x = 2^sqrt2
log2 x =- sqrt2 => x =
2^-sqrt2
All values of x that verify the
equation are: {1/2 ; 2 ; 2^sqrt2 ; 2^-sqrt2}.
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