【求完整解答及說明】中二數學題兩條

[1]
d = √(2hr)

d² = 2hr

2hr = d²

h = d²/(2r)


[2]
1/(c²-cd) + 1/(cd-d²)

= 1/[c(c-d)] + 1/[d(c-d)]

= d/[cd(c-d)] + c/[cd(c-d)]

= (d+c)/[cd(c-d)]

= (c+d)/[cd(c-d)]