Substituiere z= 2^x
-------->z - 1/z= 1 | *z
z^2 -1=z
z^2 -z -1=0 ->PQ- Formel
z_1= 1/2 +(√5)/2
z_2=1/2 -(√5)/2
---------<Resubstitution:
2^x= 1/2 +(√5)/2 und 2^x= 1/2 -(√5)/2
x *ln(2) = ln(1/2 +(√5)/2 ) und x *ln(2) = ln(1/2 -(√5)/2 )---->hat keine Lösung
Lösung:
x= (ln(1/2 +(√5)/2 ))/ ln(2)