let a, x, p, y, q be Real; :: thesis: for n being Element of NAT st a * (x |^ n) = p & x * y = q & ex m being Element of NAT st
( n = 2 * m & m >= 1 ) & p / a > 0 & a <> 0 & not ( x = n -root (p / a) & y = q * (n -root (a / p)) ) holds
( x = - (n -root (p / a)) & y = - (q * (n -root (a / p))) )

let n be Element of NAT ; :: thesis: ( a * (x |^ n) = p & x * y = q & ex m being Element of NAT st
( n = 2 * m & m >= 1 ) & p / a > 0 & a <> 0 & not ( x = n -root (p / a) & y = q * (n -root (a / p)) ) implies ( x = - (n -root (p / a)) & y = - (q * (n -root (a / p))) ) )

assume A1: ( a * (x |^ n) = p & x * y = q & ex m being Element of NAT st
( n = 2 * m & m >= 1 ) & p / a > 0 & a <> 0 ) ; :: thesis: ( ( x = n -root (p / a) & y = q * (n -root (a / p)) ) or ( x = - (n -root (p / a)) & y = - (q * (n -root (a / p))) ) )
then consider m being Element of NAT such that
A2: ( n = 2 * m & m >= 1 ) ;
A3: n >= 1 by A2, XREAL_1:163;
A4: p <> 0 by A1;
(p / a) " > 0 by A1, XREAL_1:124;
then 1 / (p / a) > 0 by XCMPLX_1:217;
then A5: (1 * a) / p > 0 by XCMPLX_1:78;
A6: x |^ n = p / a by A1, XCMPLX_1:90;
per cases ( x = n -root (p / a) or x = - (n -root (p / a)) ) by A1, A6, Th4;
suppose A7: x = n -root (p / a) ; :: thesis: ( ( x = n -root (p / a) & y = q * (n -root (a / p)) ) or ( x = - (n -root (p / a)) & y = - (q * (n -root (a / p))) ) )
then y * ((n -root (p / a)) * (n -root (a / p))) = q * (n -root (a / p)) by A1;
then y * (n -root ((p / a) * (a / p))) = q * (n -root (a / p)) by A1, A3, A5, POWER:12;
then y * (n -root ((p / a) * (a * (p " )))) = q * (n -root (a / p)) by XCMPLX_0:def 9;
then y * (n -root (((p / a) * a) * (p " ))) = q * (n -root (a / p)) ;
then y * (n -root (p * (p " ))) = q * (n -root (a / p)) by A1, XCMPLX_1:88;
then y * (n -root (p / p)) = q * (n -root (a / p)) by XCMPLX_0:def 9;
then y * (n -root 1) = q * (n -root (a / p)) by A4, XCMPLX_1:60;
then y * 1 = q * (n -root (a / p)) by A3, POWER:7;
hence ( ( x = n -root (p / a) & y = q * (n -root (a / p)) ) or ( x = - (n -root (p / a)) & y = - (q * (n -root (a / p))) ) ) by A7; :: thesis: verum
end;
suppose A8: x = - (n -root (p / a)) ; :: thesis: ( ( x = n -root (p / a) & y = q * (n -root (a / p)) ) or ( x = - (n -root (p / a)) & y = - (q * (n -root (a / p))) ) )
then y * ((n -root (p / a)) * (n -root (a / p))) = - (q * (n -root (a / p))) by A1;
then y * (n -root ((p / a) * (a / p))) = - (q * (n -root (a / p))) by A1, A3, A5, POWER:12;
then y * (n -root ((p / a) * (a * (p " )))) = - (q * (n -root (a / p))) by XCMPLX_0:def 9;
then y * (n -root (((p / a) * a) * (p " ))) = - (q * (n -root (a / p))) ;
then y * (n -root (p * (p " ))) = - (q * (n -root (a / p))) by A1, XCMPLX_1:88;
then y * (n -root (p / p)) = - (q * (n -root (a / p))) by XCMPLX_0:def 9;
then y * (n -root 1) = - (q * (n -root (a / p))) by A4, XCMPLX_1:60;
then y * 1 = - (q * (n -root (a / p))) by A3, POWER:7;
hence ( ( x = n -root (p / a) & y = q * (n -root (a / p)) ) or ( x = - (n -root (p / a)) & y = - (q * (n -root (a / p))) ) ) by A8; :: thesis: verum
end;
end;