令x=1/t,则dx=-dt/t^2；x∈[-3,-2],t∈[-1/3,-1/2]；∴∫（-3,-2）dx/x^2√(x^2-1)=∫(-1/3,-1/2)(-dt/t^2)t^2*t/√(1-t^2) =∫(-1/3,-1/2)(1/2)d(1-t^2)/√(1-t^2) ...