就 網(wǎng)上 一視頻 一結論 即 結論6. 之證明
有
R2
=
2(h-r)2(1-cosα)
/
sin2α
+
r2-(h-r)2
=
2(h-r)2(1-cosα)
/
1-cos2α
+
2rh-h2
=
2(h-r)2
/
1+cosα
+
2rh-h2
=
2(h-r)2
/
1+cosα
+
2rh-h2-r2
+
r2
=
2(h-r)2
/
1+cosα
-
(h-r)2
+
r2
=
(h-r)2(1-cosα)
/
1+cosα
+
r2
=
(h-r)2tan2(α/2)+r2
得證
標簽：
