求∫1/√20[arccosx/(1-x2)3]dx

求∫1/√20[arccosx/(1-x2)3]dx
【正确答案】:令x=cost,则有 原式=∫π/4π/2[t(-sint)/sin3t]dt =∫π/2π/4tcsc2tdt =-∫π/2π/4td(cott) =-(tcott∣π/2π/4-∫π/2π/4cottdt) =π/4+ln∣sint∣π/2π/4 =ln√2+π/4=(1/2)ln2+π/4