Re: [微積] 證明
: -----
: Sent from JPTT on my Asus ASUS_Z017DA.
d_1 tanθ_1 + d_2 tanθ_2 = a
dθ_2/dθ_1 = -(d_1/d_2) [secθ_1 / secθ_2]^2
T = [d_1 secθ_1] / v_1 + [d_2 secθ_2] / v_2
dT/dθ = (d_1 / v_1) secθ_1 tanθ_1 + (d_2 / v_2) secθ_2 tanθ_2[dθ_2/dθ_1]
= d_1(secθ_1)^2 (sinθ_1 / v_1) + d_2(secθ_2)^2 (sinθ_2 / v_2) dθ_2/
dθ_1
= d_2(secθ_2)^2(-dθ_2/dθ_1)[(sinθ_1 / v_1) - (sinθ_2 / v_2)]
要求 = 0
=> sinθ_1 / v_1 = sinθ_2 / v_2
--
※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 111.249.177.80
※ 文章網址: https://www.ptt.cc/bbs/Math/M.1493227849.A.C1C.html
→
04/27 10:30, , 1F
04/27 10:30, 1F
→
04/27 20:11, , 2F
04/27 20:11, 2F
推
04/27 20:18, , 3F
04/27 20:18, 3F
→
04/27 20:20, , 4F
04/27 20:20, 4F
推
04/27 20:43, , 5F
04/27 20:43, 5F
→
04/27 21:01, , 6F
04/27 21:01, 6F
討論串 (同標題文章)
