code: private void addTranslationJacobian( Point3D_F64 cameraPt )
  	{
  		double divZ = 1.0/cameraPt.z;
  		double divZ2 = 1.0/(cameraPt.z*cameraPt.z);
  
  		// partial T.x
  		output[indexX++] = divZ;
  		output[indexY++] = 0;
  		// partial T.y
  		output[indexX++] = 0;
  		output[indexY++] = divZ;
  		// partial T.z
  		output[indexX++] = -cameraPt.x*divZ2;
  		output[indexY++] = -cameraPt.y*divZ2;
  	}
docs: Derivative for translation element
  
  deriv [x,y] = -dot(z)*T/(z^2) + dot(T)/z
  
  where T is translation, z = z-coordinate of point in camera frame