cos 198° +sin 432°+ tan 168°+tan12° এর মান-

ব্যাখ্যা

cos198° + sin432° + tan168° + tan12° = cos(2·90° + 18°) + sin(5·90° − 18°) + tan(2·90° − 12°) + tan12° = −cos18° + cos18° − tan12° + tan12° = 0