--- a/extra/quaternion_oo/devel/RV9_Quaternions.txt	Mon Nov 14 16:24:51 2011 +0000
+++ b/extra/quaternion_oo/devel/RV9_Quaternions.txt	Mon Nov 14 16:34:11 2011 +0000
@@ -111,26 +111,24 @@
  Q = Quaternion(T) is a unit quaternion equivalent to the rotational
 
 = methods =
+DONE [c] inv       return inverse of quaterion
+DONE [e] norm:  Wraps abs from quaternions_oo
+DONE [x] dot  derivative of quaternion with angular velocity w
+DONE [c] display
+DONE [] q2tr
+DONE [*] unit      return unit quaternion
 
-DONE [c] inv       return inverse of quaterion
-By Monday, November 07 2011 this function is equivalent to the conj function of quaternions_oo
-not to inv of that package.
-
-DONE [e] norm:  Wraps abs from quaternions_oo
-
-DONE [] unit      return unit quaternion
 [] plot      same options as trplot()
 [] interp    interpolation (slerp) between q and q2, 0<=s<=1
 [] scale     interpolation (slerp) between identity and q, 0<=s<=1
-DONE [x] dot  derivative of quaternion with angular velocity w
 
 = Operators =
-[*] q+q2      return elementwise sum of quaternions
-[*] q-q2      return elementwise difference of quaternions
-[*] q*q2      return quaternion product
+DONE [*] q+q2      return elementwise sum of quaternions
+DONE [*] q-q2      return elementwise difference of quaternions
+DONE [*] q*q2      return quaternion product
+DONE [*] q/q2      return q*q2.inv
+
 [*] q*v       rotate vector by quaternion, v is 3x1
-[*] q/q2      return q*q2.inv
-
 [] q^n       return q to power n (integer only)
 
 = Properties (read only)=

--- a/extra/quaternion_oo/inst/@quaternion/power.m	Mon Nov 14 16:24:51 2011 +0000
+++ b/extra/quaternion_oo/inst/@quaternion/power.m	Mon Nov 14 16:34:11 2011 +0000
@@ -23,6 +23,10 @@
 
 function a = power (a, b)
 
+  if !isreal(b)
+    error('quaternion:InvalidArgument','Exponent must be real');
+  end
+
   if (b == -1 && isa (a, "quaternion"))
     norm2 = norm2 (a);
     a.w = a.w ./ norm2;
@@ -30,9 +34,19 @@
     a.y = -a.y ./ norm2;
     a.z = -a.z ./ norm2;
   else
-    error ("quaternion: power: case not implemeted");
+
+    na = abs (a);
+    th = acos (a.w / na);
+    n = [a.x a.y a.z] ./ sqrt((a.x).^2 + (a.y).^2 + (a.z).^2);
+
+    nab = na.^b;
+    a.w = nab .* cos (b.*th);
+
+    snt = sin (b.*th);
+    a.x = n(:,1) .* nab .* snt;
+    a.y = n(:,2) .* nab .* snt;
+    a.z = n(:,3) .* nab .* snt;
+
   endif
 
-  ## TODO: q1 .^ q2
-
-endfunction
\ No newline at end of file
+endfunction