Question: Solving nonlinear equation with fsolve

Hi guys

I'm trying to solve this equation

eqns := {(1-sin(b_u)*sin(s)/(cos(b_u-y_f)*cos(s-y_f)))*(1/cos(s-y_f)^2-1/sin(s)^2) = -(cot(s)+tan(s-y_f)+Z)*sin(b_u)*(cos(s)/cos(s-y_f)+sin(s)*sin(s-y_f)/cos(s-y_f)^2)/cos(b_u-y_f)}

where

b_u = 1/tan(0.8)
Z = 892/(27417000*f_z)
y_f = 9*Pi/180

I have a bondary condition where s=s_0 and s_0 = (1/4)*Pi-1/2*(b_u-y_f)

And i want to solve this nonlinear equation from f_z=0.00005 to f_z=0.0005 by interval 0.000001 interval

I have tryed using this topic as an example

https://www.mapleprimes.com/questions/200995-Solve-By-Newton-Raphson-Method

But in the final i'm surprised with the error "Error, (in fsolve) initial approximation does not evaluate to float"

Could someone help me please.
Thanks