mu * s,
])
-p_rightvars = p_start.subs(theta, s/r).subs(r, 1/la)
+p_rightvars = p_start.subs( theta, s/r ).subs( r, 1/la )
pprint(p_rightvars)
+
+dirn_rightvars = diff(p_rightvars, s)
+
+pprint(dirn_rightvars)
+
+zeta = Wild('zeta')
+
+p_nosing = (p_rightvars
+ .replace( 1-cos(zeta) , 2*sin(zeta/2)**2 )
+ .replace( sin(zeta)**2 , zeta*sinc(zeta)*sin(zeta) )
+ )
+p_nosing[1] = (p_nosing[1]
+ .replace( sin(zeta) , zeta * sinc(zeta) )
+ )
+
+print
+pprint(p_nosing,)
+