<prompt> Acha z iwe nambari changamano kama hiyoz frac1z frac1 sqrt52.Tafutaz85 frac1z85.  <response>: Kutoka z frac1z frac1 sqrt52,z frac1z - frac12 fracsqrt52.Kuweka pande zote mbili, tunamaliza naz2 - z frac94 - frac1z frac1z2 frac54.Kishaz2 - z 1 - frac1z frac1z2 0.Kwa hiyo, z4 - z3 z2 - z 1 0. Kishaz 1z4 - z3 z2 - z 1 0,ambayo hupanuka kama z5 1 0. Hii inatupa z5 -1.Kwa hiyo,z85 frac1z85 z517 frac1z517 - 117 frac1-117 -2. 