∫abⅇ-z⁢p⁡(t)⁢q⁡(t)⁢ⅆ⁡t∼2⁢ⅇ-z⁢p⁡(t0)⁢∑s=0∞Γ⁡(s+12)⁢b2⁢szs+(1/2),