https://wenku.baidu.com/view/3e62df30b90d6c85ec3ac670.htmlhtml
https://baijiahao.baidu.com/s?id=1614655524397070040&wfr=spider&for=pcide
已知平面上一點P,在直角座標系下座標爲(x,y),極座標系下的座標爲spa
即將$dxdy$ 轉換爲:$rdrd\theta$htm
1) $\alpha <= \theta <= \beta$; $\varphi_1(\theta) <= \theta <= \varphi_2(\theta)$blog
2) $\alpha <= \theta <= \beta$; $0 <= r <= \varphi(\theta)$get
3) $0 <= \theta <= 2\pi$; $0 <= r <= \varphi(\theta)$io