cosπ/17cos2π/17cos4π/17cos8π/17=___

来源:学生作业帮助网 编辑:六六作业网 时间:2024/12/24 00:02:46
cosπ/17cos2π/17cos4π/17cos8π/17=___cosπ/17cos2π/17cos4π/17cos8π/17=___cosπ/17cos2π/17cos4π/17cos8π/1

cosπ/17cos2π/17cos4π/17cos8π/17=___
cosπ/17cos2π/17cos4π/17cos8π/17=___

cosπ/17cos2π/17cos4π/17cos8π/17=___
看图

设t=cosπ/17cos2π/17cos4π/17cos8π/17
则tsinπ/17=sinπ/17cosπ/17cos2π/17cos4π/17cos8π/17
=(1/2)sin2∏/17cos2π/17cos4π/17cos8π/17
=(1/4)sin4∏/17cos4π/17cos8π/17
=(1/8)sin8∏/17cos8π/17
=(1/16)sin16∏/17
=(sinπ/17)/16
t=1/16

1/2

cosπ=-1;17cos2π=17cos4π=17cos8π=17
至于那‘/’是啥意思,你据题目算吧

没太看懂你的题目,大概算了一下,得
负的17的4次幂分之1 对不?LZ

cosπ/17cos2π/17cos4π/17cos8π/17
=(sinπ/17cosπ/17cos2π/17cos4π/17cos8π/17)/(sinπ/17)
=(1/2sin2π/17cos2π/17cos4π/17cos8π/17)/(sinπ/17)
=(1/4sin4π/17cos4π/17cos8π/17)/(sinπ/17)
=(1/8sin8π/17cos8π/17)/(sinπ/17)
=(1/16sin16π/17)/(sinπ/17)
=1/16

汗...高一数学好难啊..我高一刚刚结束..然后不会做.忘光了...果然,数学是弱项啊弱项啊~~
以下是网上百度的答案:
先乘sinπ/17再除sinπ/17就得到结果了
结果是1
祝,楼主数学成绩越来越好!这年头,数学几乎就是一切啊..
by_玥...

全部展开

汗...高一数学好难啊..我高一刚刚结束..然后不会做.忘光了...果然,数学是弱项啊弱项啊~~
以下是网上百度的答案:
先乘sinπ/17再除sinπ/17就得到结果了
结果是1
祝,楼主数学成绩越来越好!这年头,数学几乎就是一切啊..
by_玥

收起