三角函数[sankakukansuu] trigonometrical function
投函[toukan] mailing
函れる[ireru] to put in
函蓋[kangai] box and cover
函渠[kankyo] drain with an oblong cross-section

函人[kanjin] armorer
函嶺[kanrei] the Hakone Mountains
函数[kansuu] function (e.g. math, programming, programing)
逆函数[gyakukansuu] inverse function

に就て[nitsuite] concerning
に就き[nitsuki] because of
去就[kyoshuu] committing one's self
就いては[tsuiteha] in line with this
就きましては[tsukimashiteha] in line with this

就く[tsuku] to ascend (the throne)
就ける[tsukeru] to install (a king, emperor, etc.)
就学[shuugaku] entering school
就学義務[shuugakugimu] compulsory school attendance
就学児童[shuugakujidou] school child