是发散的.∫(0→π) 1/(cosx)^2 dx= ∫(0→π) (secx)^2 dxy = (secx)^2的定义域是x ≠ (2k + 1)π/2,k∈Z被积函数在x = π/2处不连续：= lim(ε→0+) [∫(0→π/2 - ε) (secx)^2 dx + ∫(π/2 + ε→π) (secx)^2 ...