推 ht15trep:...我要想一下= = 124.8.28.42 07/05 16:13
※ 引述《ht15trep (柏林=Boring)》之銘言：
: r = 4sin3θ
: slope of tangent line at θ=π/4 is ??
: 請問這要怎麼算= =??
: ans: 1/2
dr
設 -- = 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
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