原帖由 charityho 於 2011-5-10 06:06 PM 發表
cos 1 + cos 179 = cos 1 + cos(180-1) = cos 1 - cos 1 = 0
cos 1 + cos2 +...+ cos179+cos180 = 0 + cos 90 + cos180 = -1
similar for Q2
原帖由 nikki219 於 2011-5-10 07:27 PM 發表
假設本身tan x係60度既..
tan1/4x既 x值係15度..
姐係圖成個橫縮成原本既1/4..
你個圖又吾寫條方程,, 都吾知你岩吾岩-0-
原帖由 桃子 於 2011-5-10 09:17 PM 發表 [url=redirect.php?goto=findpost&pid=3302992&ptid=171912][/url]
Your graphs are clearly wrong.
y=tan x passes through (45 deg, 1).
y=2 tan x passes through (45 deg, 2).
y=tan x has a period of 180 deg.
y=tan (x/4) has a period of 45 deg.
原帖由 charityho 於 2011-5-10 06:06 PM 發表 [url=redirect.php?goto=findpost&pid=3302141&ptid=171912][/url]
cos 1 + cos 179 = cos 1 + cos(180-1) = cos 1 - cos 1 = 0
cos 1 + cos2 +...+ cos179+cos180 = 0 + cos 90 + cos180 = -1
similar for Q2
原帖由 桃子 於 2011-5-13 10:07 PM 發表
It looks right.
For part (c), just read the intersection from the graph.
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