Question Number 49241 by maxmathsup by imad last updated on 04/Dec/18
$${let}\:{z}\:={r}\:{e}^{{i}\theta} \:\:\:{find}\:{the}\:{value}\:{of}\: \\ $$$${P}_{{n}} =\left({z}+\overset{−} {{z}}\right)\left({z}^{\mathrm{2}} \:+\overset{−^{\mathrm{2}} } {{z}}\right).....\left({z}^{{n}} \:+\overset{−^{{n}} } {{z}}\right)\:. \\ $$