※ 引述《cabuchi (我一定要上!!!)》之銘言：
: 3.
: find the length of arch of the cycloid having parametric equations
: x=t-sint y=1-cost
t: 0 -> 2π
dx/dt = 1-cost
dy/dt = sint
2π
L = ∫√((dx/dt)^2 + (dy/dt)^2) dt = ∫√(2) √(1-cost) dt
0
= (2)∫sin(t/2)dt = 8
: 4.
: find the equation of tangent line to the graph of y=x+e^(-x)
: which perpendicular to the line 3x-y=7
找y' = -1/(3)
y' = 1 - e^(-x) = -1/3
=> e^(-x) = 4/3
=> x = -2ln2 + ln3
代入通過此(x,y)且斜率為-1/3的直線方程式即可
: 希望各位可以幫我解題
: 我明天就要考了>"< 感恩!!
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◆ From: 122.124.101.42
※ 編輯: Honor1984 來自: 122.124.101.42 (07/17 02:03)