let q, r be quaternion number ; :: thesis: q / r = ((((((((Rea r) * (Rea q)) + ((Im1 q) * (Im1 r))) + ((Im2 r) * (Im2 q))) + ((Im3 r) * (Im3 q))) / (|.r.| ^2 )) + (((((((Rea r) * (Im1 q)) - ((Im1 r) * (Rea q))) - ((Im2 r) * (Im3 q))) + ((Im3 r) * (Im2 q))) / (|.r.| ^2 )) * <i> )) + (((((((Rea r) * (Im2 q)) + ((Im1 r) * (Im3 q))) - ((Im2 r) * (Rea q))) - ((Im3 r) * (Im1 q))) / (|.r.| ^2 )) * <j> )) + (((((((Rea r) * (Im3 q)) - ((Im1 r) * (Im2 q))) + ((Im2 r) * (Im1 q))) - ((Im3 r) * (Rea q))) / (|.r.| ^2 )) * <k> )
consider q0, q1, q2, q3 being Element of REAL such that
A1: q = [*q0,q1,q2,q3*] by QUA7;
consider r0, r1, r2, r3 being Element of REAL such that
A2: r = [*r0,r1,r2,r3*] by QUA7;
A3: ( Rea q = q0 & Im1 q = q1 & Im2 q = q2 & Im3 q = q3 ) by A1, QUATERNI:23;
A4: ( Rea r = r0 & Im1 r = r1 & Im2 r = r2 & Im3 r = r3 ) by A2, QUATERNI:23;
q / r = [*(((((r0 * q0) + (r1 * q1)) + (r2 * q2)) + (r3 * q3)) / (|.r.| ^2 )),(((((r0 * q1) - (r1 * q0)) - (r2 * q3)) + (r3 * q2)) / (|.r.| ^2 )),(((((r0 * q2) + (r1 * q3)) - (r2 * q0)) - (r3 * q1)) / (|.r.| ^2 )),(((((r0 * q3) - (r1 * q2)) + (r2 * q1)) - (r3 * q0)) / (|.r.| ^2 ))*] by A1, A2, Def1
.= (((((((r0 * q0) + (r1 * q1)) + (r2 * q2)) + (r3 * q3)) / (|.r.| ^2 )) + ((((((r0 * q1) - (r1 * q0)) - (r2 * q3)) + (r3 * q2)) / (|.r.| ^2 )) * <i> )) + ((((((r0 * q2) + (r1 * q3)) - (r2 * q0)) - (r3 * q1)) / (|.r.| ^2 )) * <j> )) + ((((((r0 * q3) - (r1 * q2)) + (r2 * q1)) - (r3 * q0)) / (|.r.| ^2 )) * <k> ) by Th35 ;
hence q / r = ((((((((Rea r) * (Rea q)) + ((Im1 q) * (Im1 r))) + ((Im2 r) * (Im2 q))) + ((Im3 r) * (Im3 q))) / (|.r.| ^2 )) + (((((((Rea r) * (Im1 q)) - ((Im1 r) * (Rea q))) - ((Im2 r) * (Im3 q))) + ((Im3 r) * (Im2 q))) / (|.r.| ^2 )) * <i> )) + (((((((Rea r) * (Im2 q)) + ((Im1 r) * (Im3 q))) - ((Im2 r) * (Rea q))) - ((Im3 r) * (Im1 q))) / (|.r.| ^2 )) * <j> )) + (((((((Rea r) * (Im3 q)) - ((Im1 r) * (Im2 q))) + ((Im2 r) * (Im1 q))) - ((Im3 r) * (Rea q))) / (|.r.| ^2 )) * <k> ) by A3, A4; :: thesis: verum