∫(上限a,下线0)x^2√a^2-x^2dx -
问题描述:
∫(上限a,下线0)x^2√a^2-x^2dx -
答
∫(0→a) x²√(a² - x²) dx,令x = asinz,dx = acosz dz= ∫(0→π/2) (a²sin²z)|acosz| * (acosz dz)= a⁴∫(0→π/2) sin²zcos²z dz= a⁴∫(0→π/2) (1/4)sin²...