<prompt> Kokotacos frac2 pi7 cos frac4 pi7 cos frac8 pi7.  <response>: Acha x cos frac2 pi7 cos frac4 pi7 cos frac8 pi7. Kisha kwa utumizi unaorudiwa wa pembe mbili. fomula,anzaalignx sin frac2 pi7 sin frac2 pi7 cos frac2 pi7 cos frac4 pi7 cos frac8 pi7 frac12 sin frac4 pi7 cos frac4 pi7 cos frac8 pi7 frac14 cos frac8 pi7 cos frac8 pi7 frac18 sin frac16 pi7 frac18 sin frac2 pi7,endalignhivyo x frac18. 