如下圖所示，求解！?
回答 (1)
2020-10-29 2:07 pm
✔ 最佳答案
設 PA = x, ∠APB = ∠CPD = θ, ∠BPC = α.tan(θ) = 3/x
tan(θ+α) = 7/x,
tan(2θ+α) = 12/x
tan(θ) = tan((2θ+α)-(θ+α))
∴ 3/x = [(12/x)-(7/x)]/[1+(12/x)(7/x)
= (5/x)/(1+84/x^2)
化簡, 得
x^2 = 126
∴ x = √126 = 3√14
收錄日期: 2021-05-04 02:32:27
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20201029030042AAV6Zwh