>>854
これも簡単．余計な変数は変数変換で消すと間違えにくい．

S(h) =∫[0,a(1-√h/c)^2] b(1-√h/c-√x/a)^2 dx
= ab∫[0,t^2] (t-√u)^2 du = abt^4/6 = ab(1-√h)^4/6

V = ∫[0,c] S(h) dh = abc∫[0,1] (1-√t)^4 dt = abc/90