先做代换 y=x/a.∫√〔(a+x)/(a-x)〕dx=a^2 ∫√(1-y^2) dy再做代换 y=sin ta^2 ∫√(1-y^2) dy=a^2 ∫ cos^2 t d t= a^2 ∫ (1+cos2 t)/2 d t=a^2 (t/2+ sin 2 t/4)+C=a^2 (t+sint cost)/2+C=a^2 [arcsin (x/a)+ y...