作者Honor1984 (希望愿望成真)
看板trans_math
标题Re: [微分] 切线斜率--极座标
时间Fri Jul 4 23:47:47 2008
※ 引述《ht15trep (柏林=Boring)》之铭言：
: r = 4sin3θ
: slope of tangent line at θ=π/4 is ??
: 请问这要怎麽算= =??
: ans: 1/2
dr
设 -- = k
dθ
r + ktanθ
m = -------------
k -rtanθ
4sin(135度) + 12cos(135度)*tan(45度)
= ------------------------------------
12cos(135度) - 4sin(135度)*tan(45度)
-4 + 12
= -------------
12 - 4*(-1)*1
8
= ---------
16
1
= ---------
2
--
※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 122.124.101.171
1F：推 ht15trep:...我要想一下= = 124.8.28.42 07/05 16:13